GENERIC CONSPECTUS OF THE TRIBE ASTEREAE (ASTERACEAE)

IN NORTH AND CENTRAL AMERICA, THE ANTILLES, AND HAWAII

 

Guy L. Nesom

 

North Carolina Botanical Garden

Coker Hall CB 3280

University of North Carolina

Chapel Hill, NC 27599, U.S.A.

 

abstract

 

Descriptions and major synonyms are provided for each of the 91 genera of the tribe Astereae native or adventive in the area including North and Central America, the Antilles, and the Hawaiian islands. Brief discussions are provided for all genera, with particular attention to those where taxonomic proposals to recognize or submerge segregates may remain controversial (e.g., Aster, Chrysothamnus, Conyza, Ericameria, Grindelia, Haplopappus, Lessingia, Solidago, and others). Also included are comments on the major divisions within the tribe, number of species, geographic distributions, major taxonomic subdivisions, morphological distinctions within each genus, and references to pertinent taxonomic or taxonomically related literature for each genus.

 

resumen

 

Descriptions and major synonyms are provided for each of the 91 genera of the tribe Astereae native or adventive in the area including North and Central America, the Antilles, and the Hawaiian islands. Brief discussions are provided for all genera, with particular attention to those where taxonomic proposals to recognize or submerge segregates may remain controversial (e.g., Aster, Chrysothamnus, Conyza, Ericameria, Grindelia, Haplopappus, Lessingia, Solidago, and others). Also included are comments on the major divisions within the tribe, number of species, geographic distributions, major taxonomic subdivisions, morphological distinctions within each genus, and references to pertinent taxonomic or taxonomically related literature for each genus.

 

The tribe Astereae world-wide comprises about 3020 species in 192 genera and fourteen subtribes, in the most recent accounting. Since a recent tribal overview (Nesom 1994a), four genera have been added to the tribe: Rayjacksonia Lane & Hartman (1996; 3 species, North America), Lagenocypsela Swenson & Bremer (1994; 2 species, Pacific islands), Mtonia Beentje (1999; 1 species, Africa); and Batopilasia Nesom & Noyes (2000; 1 species, Mexico). The tribe is most diverse and abundant in North America and South America but Africa and Australia are also centers of radiation, and various members, including endemic genera, occur on all continents.

      The account at hand provides a summary and overview of the genera of North and Central America, the Hawaiian Islands, and the Antilles. The inclusion of genera in the conspectus is not constrained by phylogenetic hypotheses and the geographic coverage crosses several political boundaries. The major break in coverage and treatment is between Central America and South America. All genera represented by native species are included, as well as those represented by non-natives naturalized to various degrees. Those few known only as waifs (reported at least once from outside of cultivation but probably not now persistent or reproductive) also are included, as each of them is a cosmopolitan weed or nearly so, and there is good reason to suspect all may appear again in North America. Hawaiian taxa are included because they are of direct interest to people and agencies of the United States. Most of the diversity is concentrated in North America north of Mexico, but much floristic overlap occurs between this area and Mexico, Central America, and the Antilles. The broad geographic and phyletic coverage also offers corresponding opportunities to provide perspective on various aspects of newly revised classifications and phylogenetic analyses.

      Among the Astereae, 25 genera have only a single species in North and Central America, while 22 genera have more than 10 species. The largest genera in this region are Erigeron (259 species), Symphyotrichum (91 species), Solidago (78 species), Baccharis (45 species), Grindelia (45 species), Archibaccharis (32 species), Ericameria (31 species), Machaeranthera (30 species), Heterotheca (28 species), Eurybia (28 species), Townsendia (24 species), Gutierrezia (16 species), and Isocoma (16 species). Twenty-five, including the non-native Callistephus and Tripolium, are monotypic. Most of the genera have a significant portion of their species diversity centered north of Mexico, but none is endemic north of the contiguous 48 United States. Only eight Astereaean genera (17 species total) are strictly endemic to Mexico and Central America: Aztecaster, Batopilasia, Geissolepis, Olivaea, Osbertia, Stephanodoria, Tomentaurum, and Westoniella. Archibaccharis is restricted to Mexico and Central America, except for one species recently described from South America. One of the American species of Myriactis reaches into Venezuela, but the other five are endemic to Central America. Gundlachia is essentially endemic to the West Indies but has a few populations in northern South America. A few genera (e.g., Baccharis, Oritrophium, Laestadia, Neja) reach northward into Central America or the Antilles and/or Mexico from a primarily South American distribution. Remya is endemic to the Hawaiian Islands, and two primarily Australasian genera, Tetramolopium and Keysseria, have evolutionary radiations there. Several genera are represented by species adventive from outside the American continents: Aster (A. tataricus), Bellis, Callistephus, Calotis, Centipeda, Kalimeris, and Tripolium; of these, Calotis, Centipeda, and Tripolium were recorded as waifs and apparently have not persisted in the wild.

      An identification key to the 21 Astereaean genera of continental Central America and northern South America is provided by Cuatrecasas (1986). A full treatment of the Astereae is available for Colombia (Cuatrecasas 1969) and for Venezuela (Aristeguieta 1964). The 48 genera and 410 species of Astereae in Mexico are treated by (Nesom submitted). Strother (1997) has provided a useful synoptic key to the 32 genera of Astereae in California (matching generic concepts to the recent Jepson Manual). The genera of North and Central America, including Hawaii and the Antilles, are otherwise covered by numerous regional floristic treatments. For genera occurring in North America north of Mexico and including Hawaii and Puerto Rico, complete lists of species and their documented distribution by state and province are given by Kartesz (1999).

      Over the last decade, two large North American "catch-all" groups, Haplopappus and Aster, have been partitioned into smaller genera, some of which are distantly related among themselves (see summaries by Smith 1981; Nesom & Morgan 1990; Nesom 1994b; Lane & Hartman 1996; Xiang & Semple 1996; Semple et al. 1996). Adjustments of generic boundaries in these and other complexes remain to be made.

      A recent overview of the tribe recognized 14 subtribes (Nesom 1994a). Recognition of numerous Astereaean subtribes departed from earlier systems, where six were recognized by both Bentham and Hoffman, only three by Zhang and Bremer (1993), none by Grau (1977). The "goodness of fit" of those proposed by Nesom has been tested in varying degrees in molecular studies. Molecular data (chloroplast DNA restriction site variation) pooled by a group of researchers (Youngbae Suh, David Morgan, Beryl Simpson, and Meredith Lane) of North American genera provide initial evidence for the coherence of the subtribes Chrysopsidinae, Machaerantherinae, and Solidagininae. Other molecular studies (Morgan 1997; Noyes & Rieseberg 1999; Noyes 2000) provide varying support for some subtribes, particularly Machaerantherinae, Conyzinae, and Hinterhuberinae, but indicate that small North American genera placed in the primarily Southern Hemisphere subtribes Brachyscominae and Bellieae (=Feliciinae) (Nesom 1994a) instead form several isolated elements within a strongly defined North American clade. The “Monoptilon group” (Monoptilon and Chaetopappa) is monophyletic (Noyes & Rieseberg 1999), as is the “Pentachaeta group” (Pentachaeta, Rigiopappus, and Tracyina), but both of these small groups are autochthonous in North America and most closely related to North American genera. The “Townsendia group” also is strictly North American, but ITS data suggest that the Mexican endemic genus Geissolepis, while closely related, is not strictly a part of that group. Several of the genera placed by Nesom within the Symphyotrichinae (e.g. Boltonia, Doellingeria, Oreostemma) apparently occupy phyletic positions in the Noyes and Rieseberg analysis not clearly associated with formally delimited subtribes; these genera are informally listed below as “primitive” asters. The molecular analysis of Noyes and Rieseberg, in particular, indicates that adjustments will need to be made in the infra-tribal categories and that more categories than now described probably will be required.

      In the account that follows, descriptions and major synonyms are provided for each of the 91 Astereaean genera native or adventive in North and Central America, the Antilles, and Hawaii. Attention is given to those genera where taxonomic proposals to recognize or submerge segregates may remain controversial (e.g., Aster, Chrysothamnus, Conyza, Ericameria, Grindelia, Haplopappus, Lessingia, Solidago, and others). Choice of generitype remains equivocal for some genera. Also included are comments on the major divisions within the tribe, the number of species, geographic distribution, major taxonomic subdivisions, and morphological distinctions for each genus and references to pertinent taxonomic or taxonomically related literature for each genus. References cited at the end of this introductory section provide information and perspectives at the tribal and subtribal level.

 

tribe astereae – description

 

Annual to perennial herbs to shrubs, rarely small trees or vines, rarely dioecious (or variants). Leaves alternate (opposite within a few African and Australian genera), simple to pinnately parted. Heads solitary or in a corymboid capitulescence, sometimes modified to a secund or loosely paniculate arrangement, mostly heterogamous with bisexual disc florets and pistillate ray florets, sometimes with functionally staminate disc florets, the ray florets rarely sterile; phyllaries narrow, with an acute to rounded apex, often herbaceous, and usually in (2–)3–5 series graduated to nearly equal length; receptacles flat to convex, mostly epaleate, paleate in scattered genera or species groups, sometimes alveolate. Ray florets in 1–2(-many) series, usually with a 3–5-veined, apically acute to nearly truncate, yellow or white to blue lamina, sometimes reduced to only a tube or sometimes the pistillate florets completely absent; style branches supinate. Disc florets perfect, fertile or functionally staminate; corollas narrowly tubular or narrowly funnelform (limb not strongly differentiated from the tube) to abruptly ampliate (with differentiated limb sharply expanded above the tube), rarely asymmetrical, the lobes usually 5(–4), short and erect to spreading or sharply recurved or long and recurved-coiling; style branches pronate at maturity (vs. supinately spreading in other Asteraceae tribes), with lateral stigmatic lines and lanceolate to deltate apical ("sterile") collecting appendages, the inner surface of the branches and collecting appendages glabrous, outer surface with sweeping hairs from short-papillate to longer with rounded apices, less commonly with pointed apices; anthers with lanceolate, eglandular apical appendages, the bases truncate to slightly auriculate, rarely conspicuously "tailed" or slightly calcarate; pollen grains "helianthoid." Cypselas flattened and 2-nerved or angular to nearly terete and multi-nerved, the surfaces usually with duplex hairs, sometimes glandular; pappus usually of 1–3 or 4 series of barbellate (rarely plumose) bristles, persistent or basally caducous, the outer series or all sometimes reduced to scales or awns, or the pappus completely absent. Base chromosome number, x=9 reduced to x=8, 7, 6, 5, 4, 3, and 2.

 

subtribal classification of north and central american genera

 

Tribe Astereae Cass., J. Phys. Chim. Hist. Nat. 88:195. 1819. Type genus: Aster L.

 

1. Asterinae (Cass.) Dumort., Fl. Belg. Prodr. 66. 1827. Type genus: Aster L.

 

Heterochrominae Benth. in Benth. & J.D. Hook. [nom. invalid.], Gen. Pl. 2:177. 1873. See comments regarding "Homochrominae Benth." under Solidagininae (Nesom 1994a).

 

Genera included: Aster, Callistephus, Kalimeris, Tripolium.

 

2. Baccharidinae Less., Linnaea 5:145. 1830. Type genus: Baccharis L.

 

Baccharidoideae Kostel., Allg. Med.-Pharm. Fl. 2:665. 1833. Type genus: Baccharis L.

Heterothalaminae Endlicher, Gen. Pl. 5:372. 1837. Type genus: Heterothalamus Less.

 

Genera included: Archibaccharis, Baccharis.

 

3. Bellidinae Cass. ex D. Don in R. Sweet, Brit. Fl. Gard. 1:ad t.38. 1830. Type genus: Bellis L.

 

Genera included: Bellis.

 

4. Bellieae DC. ex Godr. in Gren. & Godr., Fl. France 2:83, 104. 1850. Type genus: Bellium L.

 

Feliciinae Nesom, Phytologia 76:205. 1994. Type genus: Felicia Cass.

 

Genera included: none (see Incertae Sedis).

 

5. Brachyscominae Nesom, Phytologia 76:203. 1994. Type genus: Brachyscome Cass. Cassini’s original spelling is maintained here (see Hind & Jeffrey 1988; Short 1988; Adolphi et al. 1989; compare Lageniferinae), with Brachycome Cass. viewed as an orthographic variant.

 

Genera included: Calotis (and see Incertae Sedis).

 

6. Chrysopsidinae Nesom, Phytologia 76:203. 1994. Type genus: Chrysopsis (Nutt.) Ell.

 

Genera included: Chrysopsis, Croptilon, Heterotheca, Osbertia, Pityopsis, Tomentaurum.

 

7. Conyzinae Horan., Char. Ess. Fam. 93. 1847. Type genus: Conyza L.

 

Erigeroneae Gren. & Godr., Fl. France 2:83, 92. 1850. Type genus: Erigeron L.

 

Genera included: Aphanostephus, Conyza, Erigeron, Neja.

 

8. Grangeinae Benth. in Benth. & J.D. Hook., Gen. Pl. 2:176. 1873. Type genus: Grangea Adans.

 

Genera included: Centipeda, Egletes.

 

9. Hinterhuberinae Cuatrec., Webbia 24:5. 1969. Type genus: Hinterhubera Sch.-Bip. ex Wedd.

 

Genera included: Aztecaster, Ericameria, Laestadia, Oritrophium, Remya, Westoniella.

 

10. Lageniferinae Nesom, Phytologia 76:207. 1994. Type genus: Lagenifera Cass. Cassini’s original spelling was Lagenifera, which he changed two years later to the variant Lagenophora, adopting the Greek rather than Latin compound form (see Bullock 1966, Hind & Jeffrey 1988, and Nicolson 1996 for divergent views and reviews of the spelling and typification). The original spelling is maintained here, with the latter viewed as an orthographic variant.

 

Genera included: Keysseria, Pseudomyriactis.

 

11. Machaerantherinae Nesom, Phytologia 76:208. 1994. Type genus: Machaeranthera Nees

 

Genera included: Benitoa, Corethrogyne, Isocoma, Grindelia, Hazardia, Lessingia, Machaeranthera, Olivaea, Oonopsis, Pyrrocoma, Rayjacksonia, Stephanodoria, Xanthisma, Xanthocephalum, Xylorhiza.

 

12. Podocominae Nesom, Phytologia 76:209. 1994. Type genus: Podocoma Cass.

 

Genera included: Laennecia, Tetramolopium.

 

13. Solidagininae O. Hoffm. in Engler & Prantl, Nat. Pflanzenf. 4(5):145. 1890. Type genus: Solidago L.

 

Homochrominae Benth. in Benth. & J.D. Hook. [nom. invalid.], Gen. Pl. 2:174. 1873. See comments in Nesom (1994a).

 

Genera included: Amphiachyris, Acamptopappus, Amphipappus, Bigelovia, Chrysoma, Chrysothamnus, Columbiadoria, Eastwoodia, Euthamia, Gundlachia, Gutierrezia, Gymnosperma, Hesperodoria, Oligoneuron, Oreochrysum, Petradoria, Solidago, Stenotus, Thurovia, Vanclevea, Xylothamia.

 

14. Symphyotrichinae Nesom, Phytologia 76:211. 1994. Type genus: Symphyotrichum Nees

 

Genera included: Almutaster, Ampelaster, Canadanthus, Psilactis, Symphyotrichum.

 

Incertae sedis

 

15. “Primitive” Asters [mostly of subtribes Asterinae or Symphyotrichinae, sensu Nesom 1994a, 1994b].

 

Genera included: Batopilasia, Boltonia, Chloracantha, Doellingeria, Eucephalus, Eurybia, Ionactis, Oclemena, Oreostemma, Sericocarpus, Tonestus.

 

16. Monoptilon group [of subtribe Feliciinae, sensu Nesom 1994a].

 

Genera included: Monoptilon, Chaetopappa.

 

17. Pentachaeta group [of subtribe Feliciinae, sensu Nesom 1994a].

 

Genera included: Pentachaeta, Rigiopappus, Tracyina.

 

18. Townsendia group [of subtribe Brachyscominae, sensu Nesom 1994a].

 

Genera included: Astranthium, Dichaetophora, Geissolepis, Townsendia.

 

acknowledgments

 

I am grateful to Bill Burke and Jeff Beam (Couch Botanical Library, UNC–CH) and Jim Massey and Mary Felton (Herbarium NCU, UNC–CH) for help with various aspects of the study. John Pruski helped in obtaining obscure literature; John Strother provided helpful comments on several nomenclatural problems and fostered changes in terminology toward greater precision.

 

references

 

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Cuatrecasas, J. 1986. Un gιnero nuevo de Astereae, Compositae, de Colombia. Anales Jard. Bot. Madrid 42:415–426.

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genera of the tribe Astereae of North and

Central America, the Antilles, and the Hawaiian islands

 

1. ACAMPTOPAPPUS (A. Gray) A. Gray, Proc. Amer. Acad. Arts 8:634. 1873.

 

Haplopappus sect. Acamptopappus A. Gray, Mem. Amer. Acad. Arts 2, 4:76. 1849.

 

Rounded shrubs from a woody taproot, mostly 2–4 dm high, the stems decumbent, the older portions gray and usually with shredding bark, spinescent with age. Leaves alternate, gray-green, sometimes in axillary fascicles, narrowly lanceolate or narrowly obovate or spatulate, 0.5–2.8 cm long, entire, 1-nerved, glabrous or with scabrous margins, not resinous. Heads pedunculate, solitary or loosely corymboid; involucres campanulate to hemispheric, 4–13 mm high; phyllaries in ca. 3 series, broadly ovate to ovate-elliptic, with broad, lacerate-hyaline margins, yellowish at the base, green at apex, reflexing at maturity; receptacle deeply alveolate. Ray florets 5–14, mostly 6–18 mm long and yellow, or absent (in A. sphaerocephalus). Disc florets perfect, fertile, the corollas yellow, funnelform, with lanceolate, reflexing lobes; style appendages triangular-lanceolate. Cypselae obconic, mostly 1.5–4 mm long, densely sericeous, the inner trichomes (closest to the cypsela wall) appressed and tortuous, the outer ascending-spreading; pappus 1–2 series of thick, broadly flattened, subequal, marginally barbellate, bristle-like scales equalling the disc corolla height, apically attenuate (ray) to spatulate (disc), with a few much shorter bristles or setae, smooth-edged or barely barbellate in A. shockleyi A. Gray. Base chromosome number, x=9. (Greek, akamptos, stiff or unbending, and pappus, in reference to the thick pappus elements.)

      Type species: Acamptopappus sphaerocephalus (Harv. & A. Gray) A. Gray.

      A genus of two species, one of them with two varieties, essentially endemic to the Mojave Desert of California, Nevada, Utah, and Arizona. These are low, white-barked, desert shrubs recognized by their solitary, pedunculate heads, few yellow rays, ovate phyllaries with broad hyaline margins, villous cypselae, and thick pappus members. Lane (1988) observed that although Acamptopappus probably shares a common heritage with Eastwoodia, Amphipappus, and Vanclevea, “they are independently derived because there are so few synapomorphies among them.” She hypothesized that these four genera are most closely related to species of the “Chrysothamnus-Ericameria-Macronema alliance.” Molecular data (Lane et al. 1996) suggest that Acamptopappus and Amphipappus may be sister taxa, with Eastwoodia and Vanclevea more distantly related.

 

references

 

Gray, A. 1849. Plantae Fendlerianae Novi-Mexicanae: An account of a collection of plants made chiefly in the vicinity of Santa Fe, New Mexico, by Augustus Fendler. Mem. Amer. Acad. Arts ser. 2, 4:1–116.

Gray, A. 1873. Notes on Compositae and characters of certain genera and species, etc. Proc. Amer. Acad. Arts 8:631–661.

Lane, M.L. 1988. Generic relationships and taxonomy of Acamptopappus (Compositae: Astereae). Madrono 35:247–265.

Lane, M.A., D.R. Morgan, Y. Suh, B.B. Simpson, and R.K. Jansen. 1996. Relationships of North American genera of Astereae, based on chloroplast DNA restriction site data. In D.J.N. Hind and H.J. Beentje (eds.). Compositae: Systematics. Vol. 1, pp. 49–77. Proc. Interntl. Compositae Conf., Kew, 1994.

 

2. ALMUTASTER A. & D. Lφve, Taxon 31:356. 1982.

 

Aster sect. Pauciflori (Rydb.) A.G. Jones, Brittonia 32:233. 1980.

 

Perennial herbs 1.5–11 dm tall, arising from slender, creeping rhizomes, with fleshy fibrous roots, the uppermost stems, leaves, and phyllaries stipitate-glandular, lower parts glabrous or glabrate. Leaves thick, linear-lanceolate to nearly filiform, with 3–5 parallel nerves, sessile and subclasping, 2–12(–23) cm long, gradually reduced upwards, bracteate in the inflorescence, the margins entire, often slightly revolute, sometimes with thin, marginal cilia. Heads on bracteate peduncles 2–8 cm long; solitary or 2–10(–30) in a loosely corymboid or paniculate inflorescence; involucres turbinate to hemispheric, 4.5–8 mm high; phyllaries in 3–4(–5) subequal series, herbaceous, lacking a white, indurated basal zone; receptacle without chaff. Ray florets pistillate, fertile, 15–30(–45) in 1 series, white or sometimes lilac-tinged. Disc florets perfect, fertile, the corollas narrowly tubular, the lobes deltate, erect; style branches with lanceolate collecting appendages. Cypselae fusiform, 2–3 mm long, terete with 7–10 thin nerves, sparsely strigose; pappus a single series of apically attenuate, subequal barbellate bristles. Base chromosome number, x=9. (For contemporary American Aster s. lat. expert Almut G. Jones.)

      Type species: Almutaster pauciflorus (Nutt.) A. & D. Lφve.

      A monotypic genus, distributed from south-central Canada (Manitoba) through the western United States into south-central Mexico, segregated without comment by Lφve and Lφve (1982). Sundberg (1986) and Nesom (1994) have provided discussions of its biology and systematic placement. A number of botanists have noted similarity between Almutaster and Psilactis, particularly in their hydrophilic tendency, glandular vestiture, and their relatively small, fusiform cypselae with numerous, pronounced ribs. Among species of Symphyotrichum, Almutaster is similar to those of subg. Symphyotrichum sect. Oxytripolium (e.g., Jones 1980a, 1980b; Semple et al. 1989) in its linear-acute leaves and small, white-rayed heads in a loose inflorescence and to those of subg. Virgulus in its vestiture, tendency for 3-nerved leaves, and cypsela morphology. Molecular data (cpDNA) of Xiang and Semple (1996) place Almutaster most closely related to sect. Oxytripolium, but Psilactis, a crucial element in interpreting relationships in this group has not been included in broad molecular analyses. Semple et al. (1989) suggested that sect. Oxytripolium be treated as a separate genus, which also would bear on the taxonomic placement of Almutaster. If placed within Symphyotrichum, Almutaster would be isolated in morphology as well as its chromosome number of 2n=18. There are no known natural hybrids between Almutaster and any other species.

 

references

 

Jones, A.G. 1980a. Classification of the New World species of Aster (Asteraceae). Brittonia 32:230–239.

Jones, A.G. 1980b. Data on chromosome numbers in Aster (Asteraceae), with comments on the status and relationships of certain North American species. Brittonia 32:240–261.

Lφve, A. and D. Lφve. 1982. IOPB chromosome number reports LXXV. Taxon 31:342–368.

Nesom, G.L. 1994. Review of the taxonomy of Aster sensu lato (Asteraceae: Astereae), emphasizing the New World species. Phytologia 77:141–297.

Semple, J.C., J.G. Chmielewski, and M.A. Lane. 1989. Chromosome number determinations in fam. Compositae, tribe Astereae. III. Additional counts and comments on generic limits and ancestral base numbers. Rhodora 91:296–314.

Sundberg, S.D. 1986. The systematics of Aster subg. Oxytripolium (Compositae) and historically allied species. Ph.D. diss., Univ. of Texas, Austin.

Xiang, C. and J.C. Semple. 1996. Molecular systematic study of Aster s. lat. and related genera (Asteraceae: Astereae) based on chloroplast DNA restriction site analyses and mainly North American taxa. In D.J.N. Hind and H.J. Beentje (eds.). Compositae: Systematics. Vol. 1, pp. 393–423. Proc. Interntl. Compositae Conf., Kew, 1994.

 

3. AMPELASTER Nesom, Phytologia 77:250. 1994.

 

Aster sect. Sagittiferi A. Gray, Synopt. Fl. 1(2):179. 1884.

Virgulus sect. Sagittiferi (A. Gray) Reveal & Keener, Taxon 30:650. 1981.

 

Weak-stemmed shrubs with a sprawling or subscandent tendency (but not twining), the “stems usually widely and diffusely branched, arching and scrambling over other vegetation to a height of 4 m or more, or forming a tangle of its own; ‘climbing’ considerably effectuated by strongly divaricate lateral branches which serve in anchoring them as growth through other vegetation takes place” (Godfrey 1988, p. 201), the branches and stems sparsely to densely hirsutulous or pilosulous, eglandular, 1–10 mm in diameter, all lignescent and perennial except the very tips. Leaves deciduous to sub-evergreen (in Chapel Hill, NC) or apparently evergreen (in Florida), 1-nerved, elliptic, oblanceolate, or oblong-oblanceolate, 2–6 cm long, entire, abruptly attenuate to a narrow, auriculate-clasping base. Heads solitary or 2–8 in short-pedicellate, loose, terminal clusters; involucres turbinate to turbinate-campanulate or hemispheric, 8–12 mm long; phyllaries in 4–6 strongly graduate series, thick, low-keeled, the outer linear-oblong to narrowly spatulate, whitish and slightly indurate, with a pronounced, nearly truncate (but sometimes basally attenuate), herbaceous apical patch on the distal 1/5, the herbaceous portion usually spreading-reflexed, the buds nearly bur-like in appearance, from the spreading phyllary apices. Ray florets 40–70, bluish to pink or lavender, 1–2.5 cm long. Disc florets perfect, fertile, tubular; style branches with narrowly triangular collecting appendages. Cypselae narrowly cylindric or slightly fusiform, 2.5–3 mm long, glabrous, with 9–12 whitish, slightly raised ribs, sometimes mottled with purplish pigmentation (at maturity); pappus a single series of apically attenuate, barbellate bristles. Base chromosome number, x=9. Illustrations of a flowering branchlet, head, and cypsela are provided in Godfrey (1988). (Greek, ampelos, vine, in reference to the scandent tendency, and aster.)

      Type species: Ampelaster carolinianus (Walt.) Nesom.

      A monotypic genus endemic to the Atlantic coastal plain from southeastern North Carolina (where now extirpated) to Florida. Godfrey (1988, p. 201) described its habitat as “marshy shores, stream banks, marshes, edges of swamps and wet woodlands, often in water,” but it can be cultivated in drier sites. Ampelaster apparently is the only species of North American Aster s. lat. that approaches a shrubby habit. Overwintering buds are formed on the largest to smallest stems, except at the very branch tips. The 2–3 “bud scales” of the minute buds, observed as the buds open in mid to late March to mid April (in Chapel Hill, NC), are purplish to green and not at all indurate. The above-ground portions are hardy in Chapel Hill, which experiences an average of 75 days where the temperature is at or below freezing. Taylor (1992) provides a photograph and notes that flowering time (in Florida) is “all year,” suggesting that the plants are evergreen in that part of their range. Cultivars in central North Carolina flower until late November and December, outlasting even Symphyotrichum (Aster) pilosum, the last of the native late-blooming asters.

      Ampelaster is similar to some species of Symphyotrichum sect. Symphyotrichum as well as to S. novae-angliae (L.) Nesom and others of Symphyotrichum subg. Virgulus (where it was placed by Semple and Brouillet 1980) in its sessile-auriculate leaves and narrow, subequal phyllaries, and 1-seriate pappus. Its chromosome number of x=9, eglandular vestiture, narrowly cylindric cypselae, and the tendency for aggregation of heads suggest an affinity with the species of Eurybia (Nesom 1994). The cpDNA phylogenetic analysis of Xiang and Semple (1996) indicates that Ampelaster lies at or near the very base of Symphyotrichum but is not closely related to subg. Virgulus within the genus.

 

references

 

Godfrey, R.K. 1988. Trees, shrubs, and woody vines of northern Florida and adjacent Georgia and Alabama. Univ. of Georgia Press, Athens.

Nesom, G.L. 1994. Review of the taxonomy of Aster sensu lato (Asteraceae: Astereae), emphasizing the New World species. Phytologia 77:141–297.

Semple, J.C. and L. Brouillet. 1980. A synopsis of North American Asters: The subgenera, sections and subsections of Aster and Lasallea. Amer. J. Bot. 67:1010–1026.

Taylor, W.K. 1992. The guide to Florida wildflowers. Taylor Publishing Co., Dallas, TX.

Xiang, C. and J.C. Semple. 1996. Molecular systematic study of Aster s. lat. and related genera (Asteraceae: Astereae) based on chloroplast DNA restriction site analyses and mainly North American taxa. In D.J.N. Hind and H.J. Beentje (eds.). Compositae: Systematics. Vol. 1, pp. 393–423. Proc. Interntl. Compositae Conf., Kew, 1994.

 

4. AMPHIACHYRIS (DC.) Nutt., Trans. Amer. Philos. Soc. 2, 7:313. 1841.

 

Brachyris Nutt. sect. Amphiachyris DC., Mem. Soc. Phys. Genθve 7:265. 1836; Prodr. 5:313. 1836.

 

Taprooted annuals, 2–10 dm tall, usually somewhat woody at the base, glabrous. Leaves alternate, linear to lanceolate, 0.5–6 cm long, 1(–3) nerved, punctate. Heads pedunculate, in a loosely organized, corymbose or paniculate inflorescence; involucres narrowly campanulate to turbinate; phyllaries in 1–2(–3) series, 1-nerved, the nerve without green margins, the lower 2/3 indurated and whitish-glutinous, with hyaline margins; receptacles alveolate, glabrous or hairy with multicellular, uniseriate trichomes. Ray florets pistillate, fertile, 7–12, yellow, sometimes drying with an orange tinge; cypselae obovate, plump, 4–9–ribbed, the surface densely strigose-sericeous, the trichomes attenuate to very slightly clavate at the apex, mostly occurring in lines between the ribs; pappus a very low corona or a ring of scales. Disc florets cylindric, short-tubed, with deltate, erect lobes, the ovaries sterile-vestigial; pappus a series of 5–8 white, basally united, linear scales with spatulate tips, the scales about equal the corolla height. Base chromosome numbers, x=4 and 5. (Greek, amphi-, around, achyron, chaff or husks, alluding to the ring of chaff-like pappus elements.)

      Type species: Amphiachyris dracunculoides (DC.) Nutt.

      A genus of two species similar to Gutierrezia in ecology and general appearance as well as most morphological details (Lane 1979, 1982). Amphiachyris dracunculoides was maintained within Gutierrezia by Cronquist (1980) without comment and by Barkley (1986), who noted that the generic disposition was “a matter of taxonomic outlook.” Amphiachyris dracunculoides is widespread in the southcentral USA; A. amoena (Shinners) Solbrig is endemic to central Texas. Amphiachyris is distinguished from Gutierrezia by glandular trichomes only on the abaxial leaf surface, disc pappus of basally united, narrowly spatulate scales equalling the disc corolla height, and abaxial nerve of the phyllaries without green borders. Other characters of Amphiachyris that have been noted as distinctive are matched by similar ones in various species of Gutierrezia: sterile-vestigial disc ovaries (also in G. microcephala); pappus members as high as the disc corollas (also in G. ramulosa); and outer involucral bracts with up to 5 vascular traces (also in G. dunalii). The distinctive receptacular trichomes characteristic of Gutierrezia are absent in A. dracunculoides but present in A. amoena. In the molecular analysis of Suh and Simpson (1991), Amphiachyris is the sister genus to Thurovia; these two, in turn, are the sister to Gutierrezia.

 

references

 

Barkley, T.M. 1986. Gutierrezia. Pp. 945–946 in Great Plains Flora Association, Flora of the Great Plains. Univ. Press of Kansas, Lawrence.

Cronquist, A. 1980. Gutierrezia. P. 137, in Vascular flora of the southeastern United States, Vol. I. Asteraceae. Univ. of North Carolina Press, Chapel Hill.

Lane, M.L. 1979. Taxonomy of the genus Amphiachyris (Asteraceae: Astereae). Syst. Bot. 4:178–189.

Lane, M.L. 1982. Generic limits of Xanthocephalum, Gutierrezia, Amphiachyris, Gymnosperma, Greenella, and Thurovia (Compositae: Astereae). Syst. Bot. 7:405–416.

Nuttall, T. 1841. Descriptions of new species and genera of plants in the natural order of the Compositae, collected ... during the years 1834 and 1835. Trans. Amer. Philos. Soc. 2, 7:283–453.

Ruffin, J. 1974. A taxonomic evaluation of the genera Amphiachyris, Amphipappus, Greenella, Gutierrezia, Gymnosperma, Thurovia, and Xanthocephalum, (Compositae). Sida 5:301–333.

Ruffin, J. 1977. Palynological survey of the genera Amphiachyris, Amphipappus, Greenella, Gutierrezia, Gymnosperma, and Xanthocephalum (Compositae). Contr. Gray Herb. 207:117–131.

Solbrig, O.T. 1960b. The status of the genera Amphiachyris, Amphipappus, Greenella, Gutierrezia, Gymnosperma, and Xanthocephalum (Compositae). Rhodora 62:43–54.

Suh, Y. and B.B. Simpson. 1991. Phylogenetic analysis of chloroplast DNA in North American Gutierrezia and related genera (Asteraceae: Astereae). Syst. Bot. 15:660–670.

 

5. AMPHIPAPPUS Torr. & A. Gray ex Gray, Boston J. Nat. Hist. 5:107. 1845.

 

Rounded shrubs 3–5 dm high, with many, divaricate banches, the branchlets glabrous, becoming leafless and spinescent, the bark pale. Leaves alternate, obovate to narrowly elliptic, 3–11 mm long, entire, short-petiolate to subsessile, ascending, glabrous or minutely scabrous. Heads 2–4 in glomerate, terminal clusters, these clusters aggregated in corymboid groups; involucres turbinate-cylindric, 4–5.5 mm high; phyllaries ovate to elliptic, 7–12 and graduate in ca. 3 series, the outer keeled; receptacles alveolate. Ray florets (0–)1–2, fertile, the lamina yellow, slightly longer than the involucre. Disc florets 3–7, with sterile ovaries, the corollas narrowly funnelform, the lanceolate lobes reflexing; style branches without functional collecting appendages. Fertile cypselae oblong-elliptic, ca. 3 mm long, somewhat flattened, moderately villous, with a pappus of one series of 15–20 slender, flattened (palea-like), basally fused, barbellate bristles ca. 1 mm long; sterile cypselae ca. 1 mm long, the pappus bristles ca. 3 mm long, tortuous-twisted. Base chromosome number, x=9. (Greek, amphi-, double or two, and pappus, in reference to the dimorphic pappus, ray cypselae and disc cypselae. “The generic name which I have chosen alludes to the combination of these two kinds of pappus in the same plant” – Gray 1845)

      Type species: Amphipappus fremontii Torr. & A. Gray ex Gray.

      A monotypic genus of the Mojave Desert in California, Nevada, Utah, and Arizona, restricted to the relatively small area where these four states are contiguous. Two geographically distinct varieties are defined primarily by the density of vestiture. Plants of Amphipappus are characterized by their low, shrubby, spinescent habit and corymboid clusters of small, few-flowered heads, functionally staminate disc florets with sterile cypselae and pappus of short, barbellate bristles, the fertile ray cypselae with pappus of longer, paleaceous bristles.

 

references

 

Gray, A. 1845. Characters of some new genera and species of plants of the natural order Compositae, from the Rocky Mountains and Upper California. Boston J. Nat. Hist. 5:104–111.

Lane, M.L. 1988. Generic relationships and taxonomy of Acamptopappus (Compositae: Astereae). Madrono 35:247–265.

Porter, C.L. 1943. The genus Amphipappus Torr. and Gray. Amer. J. Bot. 30:481–483.

Ruffin, J. 1974. A taxonomic evaluation of the genera Amphiachyris, Amphipappus, Greenella, Gutierrezia, Gymnosperma, Thurovia, and Xanthocephalum, (Compositae). Sida 5:301–333.

Ruffin, J. 1977. Palynological survey of the genera Amphiachyris, Amphipappus, Greenella, Gutierrezia, Gymnosperma, and Xanthocephalum (Compositae). Contr. Gray Herb. 207:117–131.

Solbrig, O.T. 1960b. The status of the genera Amphiachyris, Amphipappus, Greenella, Gutierrezia, Gymnosperma, and Xanthocephalum (Compositae). Rhodora 62:43–54.

 

6. APHANOSTEPHUS DC., Prodr. 5:310. 1836.

 

Keerlia DC., Prodr. 5:309. 1836.

Leucopsidium DC., Prodr. 6:43. 1837.

Aphanostephus subg. Euaphanostephus Blake, Contr. Gray Herb. 53:24. 1918.

Aphanostephus subg. Pappophanus Blake, Contr. Gray Herb. 53:24. 1918.

Aphanostephus sect. Pappophanus (Blake) Shinners, Wrightia 1:101. 1946.

Aphanostephus sect. Pappopecus Shinners, Wrightia 1:108. 1946.

 

Annuals or perennials from taproots, the stems erect to decumbent or ascending, 5–50 cm tall, usually with spreading pubescence above, deflexed below, the hairs soft to stiff. Leaves alternate, broadly oblanceolate to linear-lanceolate in outline, 1.5–5 cm long, entire to pinnatifid, sessile or petioled. Heads solitary and terminal; involucres broadly to depressed hemispheric, 3.5–8 mm high, the phyllaries with broad, scarious margins, not reflexing after release of cypselae; receptacles convex to conical, epaleate. Ray florets pistillate, fertile, in 1(–2) series, the lamina white above, with a broad, purplish midstripe beneath, closing upward at night, not coiling at maturity. Disc florets perfect, fertile, the corollas yellow with orange resin ducts, tubular to funnelform, basally bulbous-indurate in some species, with deltate, erect lobes, the tube or the limb sometimes swollen and indurated at maturity. Cypselae thick-walled, usually 4-angled, sometimes subterete, 1.1–2.2 mm long, with 4–12 grooves and rib-like thickenings, usually cupped at the summit, sparsely strigose or sometimes glabrous; pappus essentially absent, a whorl of awns or bristle-tipped awns 0.2–2 mm long, or a ring of very short, equal cilia 0.2–0.4 mm high. Base chromosome number, x=5, reduced to 4 and 3. (Greek, aphanes, obscure, stephanos, crown, apparently in reference to the low coronal pappus of some species.)

      Type species: Aphanostephus ramosissimus DC.

      A small genus of four species (eight varietal taxa) restricted to the south-central United States and the northern half of Mexico, as recognized by Turner (1984). Turner’s treatment emphasized characters of achenial vestiture and chromosome numbers to reduce the number of species from the 11 treated by Shinners (1946). Turner also considered superfluous the infrageneric categories used by Blake (1918) and Shinners (1946). The infrageneric phylogenetic reconstruction by Turner (1984), based on morphology, was largely corroborated by Elisens et al. (1992). The primitive species is A. riddellii Torr. & A. Gray, which is perennial with a base chromosome number x=5, compared to the other species, which are annuals or short-lived perennials with base chromosome numbers of 4 and 3.

      Aphanostephus is distinguished from other white-rayed Astereae by its combination of ovate-lanceolate, thin-margined phyllaries, conical receptacles, thick-ribbed, columnar, 4-angled cypselae, often bearing duplex trichomes with a coiled or recurved apex, and reduced chromosome number(s). In A. skirrhobasis var. kidderi (Blake) Turner, the pappus members may appear as relatively slender, barbellate bristles with expanded bases.

      Aphanostephus was hypothesized to be closely related to Townsendia, Astranthium, and a group of Southern Hemisphere genera (Brachyscominae) on the basis of various morphological features (Nesom 1994). In contrast, molecular data (Morgan 1990; Noyes 2000; Noyes & Rieseberg 1999) indicate that Aphanostephus has arisen from within the Conyzinae, apparently as the sister group to the E. bellioides DC. group of Erigeron. Compared to Aphanostephus, however, the entire subtribe Conyzinae (comprising Erigeron, Conyza, and related South American taxa) is otherwise markedly conservative in involucral morphology (phyllaries linear-lanceolate, without wide, thin-scarious margins), cypsela morphology and vestiture (thin-walled, flat, mostly 2-nerved, subterete and multinerved in 2 groups, the duplex hairs never glochidiate), pappus (of barbellate bristles or reduced), and base chromosome number (x=9).

 

references

 

Blake, S.F. 1918. Further new or noteworthy Compositae. Contr. Gray Herb. 53:23–30.

Elisens, W.J., R.D. Boyd, and A.D. Wolfe. 1992. Genetic and morphological divergence among varieties of Aphanostephus skirrhobasis (Asteraceae – Astereae) and related species with different chromosome numbers. Syst. Bot. 17:380–394.

Larsen, E.L. Astranthium and related genera. Ann. Missouri Bot. Gard. 20:23–44. 1933.

Morgan, D.R. 1990. A systematic study of Machaeranthera (Asteraceae) and related groups using restriction site analysis of chloroplast DNA and a taxonomic revision of Machaeranthera sect. Psilactis. Ph.D. diss., Univ. of Texas, Austin.

Nesom, G.L. 1994. Subtribal classification of the Astereae (Asteraceae). Phytologia 76:193–274.

Noyes, R.D. 2000. Biogeographical and evolutionary insights on Erigeron and allies (Asteraceae) from ITS sequence data. Pl. Syst. Evol. 220:93–114

Noyes, R.D. and L.H. Rieseberg. 1999. ITS sequence data support a single origin of North American Astereae (Asteraceae) and reflect deep geographic divisions in Aster s.l. Amer. J. Bot. 86:398–412.

Shinners, L.H. 1946. Revision of the genus Aphanostephus DC. Wrightia 1:95–121.

Turner, B.L. 1984. Taxonomy of the genus Aphanostephus (Asteraceae – Astereae). Phytologia 56:81–101.

 

7. ARCHIBACCHARIS Heering, Jahr. Hamb. Wissensch. Anst. 21, Beiheft 3:40. 1904.

 

Hemibaccharis Blake, Contr. U.S. Natl. Herb. 20:544. 1924.

 

Perennial herbs, shrubs or subscandent shrubs, or scandent vines, ca. 4–65 dm tall to high-climbing, sometimes with stipitate or sessile resin glands, not punctate or glutinous, the stems straight, twining, or fractiflex (perceptibly angled at the nodes). Leaves alternate, petiolate or sessile. Heads in terminal or axillary cymose or corymboid panicles; unisexual (the species then dioecious) or sometimes displaying a diminished gynomonoecious condition. Pistillate heads 2–15 mm high, the phyllaries in 3–5 graduate series, with fertile outer pistillate florets and central (disc) morphologically hermaphroditic florets with sterile anthers and sterile, rarely fertile, cypselae; lamina of the pistillate florets well-developed or reduced (in A. peninsularis all florets uniformly tubular with distinct but reduced lobes and vestigial anthers). Staminate heads with hermaphroditic disc florets with abortive, rarely fertile cypselae, always in 3 species and sporadically in many species with outer pistillate florets with fertile cypselae, in the monoecious A. androgyna the central hermaphroditic florets with sterile cypselae. Fertile cypselae compressed, ovate, oblong, or elliptic, 0.9–2(–2.6) mm long, 2–5(–7) nerved, mostly trigonous, glabrous to strigose, sessile-glandular at the base in some; pappus 1-seriate, the bristles barbellate, with apices usually dilated on the disc florets and sometimes slightly so on the pistillate florets, not elongating at maturity. Base chromosome number, x=9. (Greek, arche, old, and Baccharis, implying that Archibaccharis is primitive relative to Baccharis.)

      Type species: Archibaccharis hieraciifolia Heering (= A. auriculata (Hemsl.) Nesom).

      A genus of 32 species, primarily Mexican and Central American; 25 occur in Mexico; 4 are endemic to Central America; one is from South America. Six sections are recognized (Nesom 1991), based on a combination of vegetative and reproductive features. The description of the first species known from South America (from Bolivia, Robinson 1997) is based only on a staminate plant, emphasizing the habital resemblance, including the subscandent habit and “loose corymbose inflorescences with deflected branching and slender peduncles.” It is superficially similar to A. hirtella but different in the basally trinerved leaves.

      Archibaccharis and Baccharis are closely related, but species of Archibaccharis are more discrete in morphology, infraspecific variation is more limited in most species, and the genus has produced a number of narrow endemics in Mexico and Central America. In addition, plants of Archibaccharis appear to be consistently scandent or at least very lax-stemmed, although a few species of Baccharis have nearly the same habit. Blake (1924, p. 544) noted the following: “This genus, which I propose to call Hemibaccharis, in allusion to the fact that the staminate plant is indistinguishable from Baccharis, will then be distinguished from Baccharis by the presence of hermaphrodite florets in the center of the pistillate heads, perhaps also by its compressed 2-nerved achenes.”

 

references

 

Blake, S.F. 1924. Hemibaccharis, a new genus of Baccharidinae. Contr. U.S. Natl. Herb. 20:543–554.

Heering, W. 1904. Die Baccharis – Arten des Hamburger Herbars. Jahr. Hamb. Wissensch. Anst. 21, Beiheft 3:39–42.

Jackson, J.D. 1975. A revision of the genus Archibaccharis Heering (Compositae–Astereae). Phytologia 32: 81–194.

Nesom, G.L. 1988. Studies in Mexican Archibaccharis (Compositae: Astereae). Phytologia 65:122–128.

Nesom, G.L. 1991. Two new species of Archibaccharis (Asteraceae: Astereae) from Mexico with a reevaluation of sectional groupings in the genus. Phytologia 71:152–159.

Nesom, G.L. 1998. Two new species of Archibaccharis (Asteraceae: Astereae) from Mexico. Phytologia 84:50–52.

Robinson, H.E. 1997. New species of Archibaccharis and Baccharis from Bolivia and Peru (Asteraceae: Astereae). BioLlania Ed. Esp. 6:501–508.

 

8. ASTER L., Sp. Pl. 872. 1753.

 

Diplactis Raf., Fl. Tellur. 2:45. 1836 [1837].

 

Perennial herbs, subshrubs, or shrubs. Leaves basal or basal and cauline or only cauline, alternate. Heads solitary to corymboid or loosely paniculate; involucres hemispheric or campanulate; phyllaries in several imbricated series; receptacle flat or convex, without chaff. Ray florets pistillate, fertile, white, pink, purple, to blue or violet. Disk florets perfect, fertile, tubular, usually yellow and remaining so at maturity. Cypselae obovate and compressed to cylindric, often glandular; pappus of 1-several series of barbellate bristles. Base chromosome number, x=9. (Greek, aster, a star.)

      Lectoype species: Aster amellus L. (Britton & Brown 1913).

      The recent, comprehensive realignment of generic boundaries among the American species of Aster s. lat. (Nesom 1994) is based on morphology and cytology, especially achenial features and chromosome morphology, which indicate that Old World Aster is more similar to accepted genera of the Old World than to New World genera and that many of the American species groups are phyletically coherent. Aster, however, even in its more restricted morphological definition, still encompasses a great deal of variation and the description remains correspondingly general. The genus still includes about 180 Old World species, among which numerous species groups can be discerned. Some of the latter almost certainly deserve status as distinct genera, coordinate with those genera already recognized within the “Kalimeris group,” the “Galatella group,” and the “Asterothamnus group” (Nesom 1994, which see for additional synonyms for Old World groups).

      Aster amellus and its closest relatives (sect. Aster, including Aster sect. Macrocephali (Kit.) A.G. Jones; see Nesom 1994) occur in Europe westward to the Himalayas in southwest Asia. These species are characterized by leafy stems, a loosely corymboid (or sometimes monocephalous) inflorescence, apically herbaceous phyllaries in ca. 3 gradate series, abruptly ampliate disc corollas, style branches with deltate-papillate collecting appendages, obovate, strongly flattened cypselae with sessile-glandular faces and a pair of lateral ribs, a 2–3 seriate pappus, the inner bristles often apically dilated, the outer series often shorter, and chromosomes with “Asterinae type” of NOR morphology. Other Old World groups, including sect. Ageratoides (Kitam.) Nesom and sect. Alpigeni Nees, considerably broaden the concept of the genus, especially in habit, inflorescence, and involucral bract morphology, but cypsela morphology is relatively constant (Grierson 1964). Natural hybrids have been recorded between species of sect. Ageratoides and several of the genera Heteropappus Less. and Kalimeris (see comments under the latter). Infrageneric categories within Asian Aster have been variously modified in recent treatments by Ling et al. (1985), as summarized by Nesom (1994).

      As tentatively accepted here, only two species of Aster s. str. occur in North America outside of cultivation. Aster alpinus L., the type of Aster sect. Alpigeni Nees, is primarily a Eurasian species but has a trans-Beringian distribution and occurs naturally southward along the Rocky Mountain cordillera, broadly through Canada, and disjunct southward into Colorado. Its obovate, strongly flattened, apically glandular cypselae are similar to those of typical Aster (sect. Aster), and natural hybrids between A. alpinus and A. amellus were reported by Tamamschyan (1959). On the basis of cpDNA evidence, Semple (in Semple et al. 1996) has transferred A. alpinus and A. tongolensis Franchet to the genus Diplactis, noting that other, unspecified Old World species also may be congeneric.

      Aster tataricus L.f., a native of northeastern Asia, is cultivated widely in eastern North America for the tall, leafy plants bearing many blue-rayed heads and has escaped in many places across the eastern United States. The cypselae are terete, 5–7 nerved, and eglandular with a pappus of 2 equal-length series of bristles. This species and a closely similar species will be considered for status as a separate genus, perhaps related to Doellingeria (Nesom 1994, p. 160).

      Jones and Young (1983), based on analyses of morphological and cytological data, maintained all New World species within Aster. Xiang and Semple (1996) and Semple et al. (1996) recognized some segregates but maintained large groups of American species within Aster s. str., based on cpDNA data indicating that the Old World generitype of Aster s. str. (A. amellus) is phyletically imbedded within one of the North American groups (the genus Eurybia, as treated here). As viewed by Nesom (1994, 1997), A. amellus is isolated within Eurybia and its placement there is not supported by morphological or cytological evidence. The molecular analysis of Noyes and Rieseberg (1999) also indicates that the New World species are phyletically separate from the Old World ones, if indeed Sericocarpus and Eurybia are closely related, as postulated by Nesom (1994) and Xiang and Semple (1996). The Noyes and Rieseberg study included Sericocarpus but not Eurybia.

      Most of the remainder of the nearly 180 native American species previously identified as Aster in the broad sense are divided here among Almutaster, Ampelaster, Canadanthus, Doellingeria, Eucephalus, Eurybia, Ionactis, Oclemena, Oreostemma, Sericocarpus, and Symphyotrichum. Other North American species more or less recently included in Aster are now apportioned among Machaeranthera, Xylorhiza, Psilactis, and Tonestus. All of these genera evolved from a broad lineage that apparently includes only other North American species (Noyes & Rieseberg 1999). Doellingeria, which appears to be a phyletically primitive element of this American lineage, is an exception with New World and Old World species.

 

references

 

Britton, N.L. and A. Brown. 1913. An illustrated flora of the northern United States, Canada, and the British Possessions (ed. 2). Vol. 3. Lancaster Press, Lancaster, Penn.

Grierson, A.J.C. 1964. A revision of the asters of the Himalayan area. Notes Royal Bot. Gard. Edinb. 26:67–163.

Ito, M., A. Soejima, and T. Nishino. 1994. Phylogeny and speciation of Asian Aster. Korean J. Pl. Taxon. 24:133–143.

Ito, M. and A. Soejima. 1995. Aster L. In K. Iwatsuki, T. Yamazaki, D.E. Boufford, and H. Ohba (eds.). Flora of Japan 3b:59–73.

Ito, M., A. Soejima, and K. Watanabe. 1998. Phylogenetic relationships of Japanese Aster (Asteraceae, Astereae) sensu lato based on chloroplast-DNA restriction site mutations. J. Pl. Res. 111:217–223.

Jones, A.G. and A. Smogor. 1983. Chromosome counts of and notes on some Old World Asters (Asteraceae). Phytologia 53:429–431.

Jones, A.G. and D. Young. 1983. Generic concepts of Aster (Asteraceae): A comparison of cladistic, phenetic, and cytological approaches. Syst. Bot. 8:71–84.

Ling, Y., Y.-l. Chen, and Z. Shi. 1985. Flora Reipublicae Popularis Sinicae, Compositae (1), [Astereae]. Tomus 74:73–353.

Nesom, G.L. 1994. Review of the taxonomy of Aster sensu lato (Asteraceae: Astereae), emphasizing the New World species. Phytologia 77:141–297.

Nesom, G.L. 1995. Key to the American genera of Asterinae (Asteraceae). Phytologia 79:281–285.

Nesom, G.L. 1997. Taxonomic adjustments in North American Aster sensu latissimo (Asteraceae: Astereae). Phytologia 82:281–288.

Noyes, R.D. and L.H. Rieseberg. 1999. ITS sequence data support a single origin of North American Astereae (Asteraceae) and reflect deep geographic divisions in Aster s.l. Amer. J. Bot. 86:398–412.

Semple, J.C. and L. Brouillet. 1980. A synopsis of North American Asters: The subgenera, sections and subsections of Aster and Lasallea. Amer. J. Bot. 67:1010–1026.

Semple, J.C., S.B. Heard, and C.S. Xiang. 1996. The Asters of Ontario (Compositae: Astereae): Diplactis Raf., Oclemena E.L. Greene, Doellingeria Nees and Aster L. (including Canadanthus Nesom, Symphyotrichum Nees, and Virgulus Raf.). Rev. ed. Univ. of Waterloo Biol. Ser. 38:i–viii, 1–94.

Xiang, C. and J.C. Semple. 1996. Molecular systematic study of Aster s. lat. and related genera (Asteraceae: Astereae) based on chloroplast DNA restriction site analyses and mainly North American taxa. In D.J.N. Hind and H.J. Beentje (eds.). Compositae: Systematics. Vol. 1, pp. 393–423. Proc. Interntl. Compositae Conf., Kew, 1994.

 

9. ASTRANTHIUM Nutt., Trans. Amer. Philos. Soc. 2, 7:312. 1841.

 

Annual, biennial, or perennial herbs from a taproot or fibrous roots, the stems erect (or also creeping in 1 species), 5–50 cm tall, sparsely to densely hairy, 1–5 dm tall. Leaves mostly entire, sometimes few-toothed, the lower spatulate-obovate, narrower above, 1–8(–12) cm long, clasping to subclasping in some, glabrous or hairy. Heads solitary, usually on long, leafless or bracteate peduncles; involucres campanulate or hemispherical, 3.5–8 mm high; phyllaries in 2(–3) nearly equal series, broadly oblanceolate to linear-lanceolate, thin-herbaceous, often with hyaline margins; receptacle conical. Ray florets pistillate, fertile, 10–65(–85), white above, drying white beneath or with a blue to purplish-blue midstripe. Disc florets perfect, fertile, the corollas yellow, usually abruptly and strongly contracted near the base to a short tube; style branches with lanceolate-acute appendages. Cypselae obovate to oblanceolate-obovate, 1.2–3.5 mm long, laterally compressed, usually with 2 thin marginal nerves, with 2 thick marginal ribs in 2 species, surfaces smooth or most commonly papillate-pebbly, glabrous or with duplex, glochidiate hairs; pappus absent or a crown of setae or scales less than 0.1 mm high. Base chromosome numbers, x= 3, 4, 5. (Greek, astron, star, anthos, flower)

      Type species: Astranthium integrifolium (Michx.) Nutt.

      A genus of 11 species, all but two restricted to Mexico (De Jong 1965; Rzedowski 1983). Astranthium robustum (Shinners) De Jong is endemic to Texas and A. integrifolium ranges from northeastern Mexico into the south-central USA. The species are separated by small but consistent morphological differences, often accompanied by differences in chromosome number, and they are geographically coherent. Astranthium is characterized by a herbaceous habit with solitary heads on long peduncles, conical receptacles, phyllaries in 2–3 series of equal length, white or blue rays, short-tubed disc corollas, flattened, papillate-surfaced cypselae with pappus absent or a short corona. Vegetatively and florally, Astranthium is similar to the monotypic Dichaetophora (see comments following) and the latter has the same chromosome number (n=3 pairs) as northern species of Astranthium. Epappose species of Erigeron may be superficially similar to Astranthium (De Jong & Nesom 1982) but they are distantly related.

 

references

 

De Jong, D.C.D. 1965. A systematic study of the genus Astranthium (Compositae, Asteraeae). Michigan State Univ. Mus. Publ. Biol. Ser. 2: 429–528.

De Jong, D.C.D. and G.L. Nesom. 1982. Erigeron astranthioides (Asteraceae: Astereae), a new epappose species from western Mexico. Brittonia 34:285–289.

Larsen, E.L. 1933. Astranthium and related genera. Ann. Missouri Bot. Gard. 20:23–44.

Nuttall, T. 1841. Descriptions of new species and genera of plants in the natural order of the Compositae, collected ... during the years 1834 and 1835. Trans. Amer. Philos. Soc. 2, 7:283–453.

Rzedowski, J. 1983. Does especies nuevas de Compositae – Astereae del Valle de Mιxico. Bol. Soc. Bot. Mιxico 45:111–116.

 

10. AZTECASTER Nesom, Phytologia 75:64. 1993.

 

Shrubs 0.5–1.6 m tall, with rigid, straight branches, the young stems densely and closely silvery-white pannose, glabrate with age. Leaves densely arranged along the stems, commonly with axillary fascicles, linear-oblong, 4–26 mm long, entire, ericoid with strongly revolute margins, lightly flocculent, quickly glabrescent, glutinous. Heads sessile, axillary (each head immediately subtended by a cluster of leaves), in a open cylindric-spicate panicle; each head either with functionally pistillate florets or functionally staminate florets, the pistillate and staminate heads on separate plants and the species dioecious. Pistillate involucres 6–8(–10) mm long, the staminate heads slightly smaller; phyllaries in 3–4 graduated series, narrowly triangular to narrowly ovate, with scarious margins, stramineous to greenish-yellow, resinous, indurated and even-textured, narrowly keeled; receptacle barely alveolate. Pistillate florets 5–10 per head, the corollas regular, narrowly tubular, 5-lobed. Staminate (pseudohermaphroditic) florets with abortive ovaries, 8–9 per head, the corollas regular. Cypselae oblong-obovate, flat with a nerve at each margin or sometimes with an additional nerve in the middle of one or both faces, 2.5–3 mm long, strigose with duplex hairs; pappus 1-seriate, of numerous barbellate bristles with attenuate apices. Base chromosome number, unknown, predicted x=9. (In reference to a native people of central Mexico.)

      Type species: Aztecaster pyramidatus (B. Rob. & Greenm.) Nesom.

      Aztecaster comprises two similar but widely allopatric species endemic to Mexico. Both are glutinous, dioecious shrubs with white-pannose stems, ericoid leaves, discoid heads in a open-spicate inflorescence, strongly indurated phyllaries, actinomorphic outer (pistillate) corollas with five apical lobes, disc corollas with long lobes, and flattened cypselae. They are the only dioecious species of Astereae reported outside of American Baccharidinae, where this sexual condition has been independently derived. The two species of Aztecaster were earlier treated as species of Baccharis (Rzedowski 1972) (one was previously transferred from Bigelowia to Chrysothamnus), but they apparently are more closely related to the North American Ericameria and genera in the subtribe Hinterhuberinae, a group centered primarily in South America but also reaching Australasia and Africa (Nesom 1993, 1994).

 

references

 

Nesom, G.L. 1993. Aztecaster (Asteraceae: Astereae), a new ditypic genus of dioecious shrubs from Mexico with redefinitions of the subtribes Hinterhuberinae and Baccharidinae. Phytologia 75:55–73.

Nesom, G.L. 1994. Subtribal classification of the Astereae (Asteraceae). Phytologia 76:193–274.

Rzedowski, J. 1972. Tres adiciσnes al gιnero Baccharis (Compositae) en Mιxico. Brittonia 24:398–402.

 

11. BACCHARIS L., Sp. Pl. 860. 1753 [nom. conserv. prop., Hellwig 1989].

 

Molina Ruiz & Pavon, Prodr. Fl. Peruv. 3:200. 1794 [non Molina Cav. 1790].

Neomolina Hellwig, Candollea 48:211. 1993 [non Neomolinia Honda & Sakis 1930]. (proposed by Hellwig to replace Molina Ruiz & Pavon)

Sergilus Gaertner, Fruct. Sem. Pl. 2:409. 1791.

Tursenia Cass., Dict. Sci. Nat. 37:480. 1825.

Pingraea Cass., Dict. Sci. Nat. 41:57. 1826.

Baccharidastrum Cabrera, Not. Mus. La Plata Bot. 2:175. 1937.

 

Small trees or shrubs, subshrubs, or perennial herbs, 0.1–8 m tall, rarely prostrate or scandent, dioecious or rarely monoecious, commonly glabrous. Leaves alternate or rarely opposite, simple, linear to ovate or obovate or spatulate, 1–13 cm long, 1-nerved to 3-nerved from the base or pinnate-veined, sessile or petiolate, entire to toothed, glabrous or short-hairy, usually punctate-glandular and resinous, commonly coriaceous or subcoriaceous, rarely tomentose or arachnoid beneath, sometimes reduced to thorns, scales, or wings, or absent. Heads sessile or pedicellate, usually in a corymboid or paniculate-corymboid inflorescence, less commonly solitary; involucres cylindric, campanulate, to hemispheric, 4–8.5 mm high; phyllaries in 3–8 graduated series; receptacles nearly flat to convex, epaleate or paleate in one group. Heads discoid, unisexual, sessile or short-pedunculate, in thyrsoid panicles or corymboid aggregations, less often racemoid, spicate, or solitary; staminate heads with morphologically bisexual florets but sterile ovaries, the corollas funnelform with narrow, spreading-reflexing lobes cut nearly to the base of the limb, mostly whitish to purplish, style branches without stigmatic lines; pistillate heads with filiform-tubular corollas with short teeth or lobes. Cypselae oblong to narrowly fusiform, 1–4.5 mm long, compressed to nearly terete, glabrous or hairy, with 5–10(–12) thin, light-colored nerves; pappus of 1–3 series of barbellate bristles, those of the staminate heads often apically dilated, those of the pistillate heads usually elongating at maturity well past the involucral bracts, basally caducous in sect. Baccharis. Base chromosome number, x=9. (For Bacchus, the Roman god of wine, the allusion to the genus unclear.)

      Type species: Baccharis halimifolia L. [typ. cons. prop., Hellwig 1989]

      Baccharis is a New World genus including 350–450 species, about 90% of which are centered in South America. Five are endemic to North America north of Mexico; 38 others occur in Mexico and continental Central America (Nesom 1990a, 1990b, 1998; Nesom 2000), many of these with part of the range in the United States; an additional six or seven endemic species occur in the West Indies. Recent taxonomic treatments are available for species of a number of regions, e.g., central Argentina (Espinar 1973), Brazil (Barroso 1976), Chile (Hellwig 1990, for Baccharis s. str.), Colombia (Cuatrecasas 1967, 1989), Mexico (Matuda 1957; Nesom 2000), and the south-central USA (Mahler & Waterfall 1964). Cuatrecasas (1967) outlined the composition of major groups (mostly at sectional rank) and clarified the typification for many of them. Guiliano (in press) provides a review and infrageneric classification of the 96 species in Argentina.

      Most of the species of Baccharis are dioecious shrubs with punctate-resinous leaves. The genus is closely related to Archibaccharis, which can be distinguished by examination of the pistillate heads, which nearly always retain 1–5 staminate florets, usually completely sterile; staminate heads of Archibaccharis may also possess 1–5 ray florets that are also characteristically sterile. Considerable variation exists in Baccharis and the American Baccharidinae with respect to the modal dioecious expression of sexuality (Hellwig 1990, 1996; Zanowiak 1991). Each plant of a Mexican species described as B. monoica Nesom (1988a) always produces both pistillate and staminate heads, but this species is derived from the typically dioecious B. salicifolia (Ruiz & Pavon) Pers., a member of the “Molina group.” Monoecious and dioecious species also exist in sect. Baccharidastrum (Cabrera) Nesom (Nesom 1988b), a member of the “Pingraea group;” heads of the monoecious species, which almost certainly are derived from dioecious ancestors) have numerous, outer, pistillate florets with a few, central functionally staminate ones.

      Hellwig (1993, 1996) has begun to lay groundwork for an overview of the genus and subtribe; in his approach he has begun to divide Baccharis into a number of generic-level segregates, primarily based on features of vestiture (Hellwig 1992), cypsela morphology, and other fruit and floral characters, many of which were studied earlier in detail by Barroso (1976). As yet, Hellwig has not formally included all of the species that belong in these groups and he has not provided an complete overview or rationale for treating these species groups at generic rather than infrageneric rank. Zanowiak’s cpDNA molecular-phylogenetic study (1991) included species from a taxonomically limited range of groups of American Baccharidinae (Archibaccharis, Heterothalamus, Baccharis s. str., and Pingraea and Neomolina sensu Hellwig), but her data provide a preliminary rationale for maintaining a broadly defined and largely undivided Baccharis. The generally recognized genera Archibaccharis and Heterothalamus are sister groups and are phylogenetically basal to the rest of Baccharis s. lat. Pingraea and Neomolina are sister groups and most closely related to Baccharis s. str. Numerous morphological subgroups can be distinguished within these larger taxa. The ultimate classification of American Baccharidinae probably will be influenced by the relationship of other smaller Baccharis segregates regarded as valid genera or generic-level taxa by Hellwig: Baccharidiopsis Barroso, Pseudobaccharis Cabrera, Stephananthus Lehm. (including Palenia Phil. and Psila Phil.), and two other groups considered by Hellwig to represent generic-level taxa, “Lanugobaccharis,” and “Heterothalamus boliviensis.”

 

references

 

Barroso, G.M. 1976. Compositae–Subtribo Baccharidinae Hoffman – Estudo das especies ocorrentes no Brasil. Rev. Rodriguesia 40:3–273.

Beauchamp, R.M. 1980. Baccharis vanessae, a new species from San Diego County, California. Phytologia 46:217–222.

Beauchamp, R.M. and J. Henrickson. 1995. Baccharis malibuensis (Asteraceae): A new species from the Santa Monica Mountains, California. Aliso 14:197–203.

Boldt, P.E. 1989. Baccharis, (Asteraceae), a review of its taxonomy, phytochemistry, ecology, economic status, natural enemies and the potential for its biological control in the United States. MP 1674, Texas Agric. Exp. Stat., Texas A&M Univ., College Station.

Cabrera, A.L. 1955. La identidad del gιnero Psila Phillippi. Bol. Soc. Argentina Bot. 5:209–211.

Cuatrecasas, J. 1967. Revisiσn de las especies Colombianas del gιnero Baccharis. Revista Acad. Colombiana Ci. Exactas, Fis. & Nat. 13:5–102.

Espinar Ariza, L. 1973. Las especies de Baccharis (Compositae) de Argentina central. Bol. Acad. Nac. Cienc. Argentina 50:175–305.

Guiliano, D.A. In press. Clasificaciσn infragenιrica de las especies argentinas de Baccharis (Asteraceae, Astereae). Darwiniana.

 Hellwig, F.H. 1989. Proposal to conserve 8933 Baccharis L. (Asteraceae) with a conserved type. Taxon 38:513–515.

Hellwig, F.H. 1990. Die gattung Baccharis L. (Compositae – Astereae) in Chile. Mitt. Bot. Staatssamml. Mόnchen 29:1–456.

Hellwig, F.H. 1992. Untersuchungen zur Behaarung ausgewδhlter Astereae (Compositae). Flora 186:425–444.

Hellwig, F.H. 1993. The genera Pingraea Cass. and Neomolina Hellwig (Compositae – Astereae). Candollea 48:203–219.

Hellwig, F.H. 1996. Taxonomy and evolution of Baccharidinae (Compositae). In D.J.N. Hind and H.J. Beentje (eds.). Compositae: Systematics. Vol. 1, pp. 575–590. Proc. Interntl. Compositae Conf., Kew, 1994.

Mahler, W.F. and U.T. Waterfall. 1964. Baccharis (Compositae) in Oklahoma, Texas and New Mexico. Southw. Naturalist 9:189–202.

Matuda, E. 1957. El. gιnero Baccharis en Mιxico. Anales Inst. Biol. Mιxico. 28:143–174.

Nesom, G.L. 1988a. Baccharis monoica, a new species from the Baccharis salicifolia complex of

Central America. Phytologia 65:160–164.

Nesom, G.L. 1988b. Baccharis sect. Baccharidastrum (Compositae: Astereae), including two monoecious and one dioecious species. Phytologia 65:169–173.

Nesom, G.L. 1990a. Infrageneric taxonomy of North and Central American Baccharis (Asteraceae: Astereae). Phytologia 69:40–46.

Nesom, G.L. 1990b. Two new species of Mexican Baccharis (Asteraceae: Astereae). Phytologia 69:32–39.

Nesom, G.L. 1998. Two newly recognized species of Baccharis (Asteraceae: Astereae) from Mexico. Phytologia 84:43–49.

Nesom, G.L. 2000. Astereae. The Comps of Mexico. A systematic account of the family Asteraceae, Vol. II. Phytologia Memoirs, in press.

Rzedowski, J. 1983. Dos especies nuevas de Compositae – Astereae del Valle de Mιxico. Bol. Soc. Bot. Mιxico 45:111–116.

Teodoro, L.I. 1958. Novum Index Baccharidinarum (Compositae). Contr. Inst. Geobiol. Canoas 9:3–35.

Zanowiak, D.J. 1991. An analysis of systematic and phyletic relationships within the Baccharidinae (Asteraceae: Astereae). Ph.D. diss., Texas A&M Univ., College Station.

 

12. BATOPILASIA Nesom & Noyes, Sida 19(1), in press. 2000.

 

Perennial, caespitose, glabrous herbs from a system of thin, lignescent rhizomes and rhizome-like caudex branches. Stems 7–20 cm tall, usually with 1–2 ascending branches near midstem. Basal leaves persistent in rosettes, sessile, narrowly elliptic-oblanceolate, 8–26 mm long, 1–2 mm wide, entire, 1-nerved or faintly 3-nerved, the cauline leaves few and sharply reduced in size to linear bracts. Heads solitary on nearly naked peduncles, erect in bud; involucres 5–8 mm wide; phyllaries in 3–4 strongly graduated series, elliptic-oblanceolate with obtuse to acute apices, thin-herbaceous with scarious margins and 1–3, filiform, orange-resinous nerves; receptacles apparently low-convex. Ray flowers 9–18, fertile, the corollas white, drying white or purplish, 5–7 mm long, the lamina 1.4–2 mm wide, coiling at the tips. Disc flowers 24–29, fertile, the corollas not inflated or indurated, lobes triangular-deltate, erect; style branches with deltate collecting appendages. Cypselae sparsely strigose, cylindrical and terete to slightly flattened, 1.8–2.5 mm long, with (2–3)4(–5) thin, orange nerves; pappus of one series of barbellate bristles and a few outer setae. Base chromosome number, x=9. (In reference to the region of Municipio Batopilas in southwestern Chihuahua, Mexico, where the plants occur.)

      Type species: Batopilasia byei (Sundberg & Nesom) Nesom & Noyes

      A monotypic genus apparently restricted to the general area of the Barranca del Cobre in southwestern Chihuahua, Mexico. The plants grow in pine-oak woodlands on steep rocky slopes, commonly in rock crevices and ledges in arroyos and canyons. They are characterized by a caespitose habit from a system of slender rhizomes and caudex branches, clustered basal rosettes, cauline leaves reduced in size and distribution, green-glabrous stems and leaves, long-pedunculate, small, few-flowered heads, rounded phyllaries with three, orange-resinous nerves, fertile ray and disc flowers, short, white, coiling ray corollas, style branches with deltate collecting appendages, and subterete, 4–5-nerved cypselae with a persistent pappus of barbellate bristles.

      In the original description of the species (as Erigeron byei, Sundberg & Nesom 1990), it was regarded as most similar to E. oxyphyllus Greene and E. ortegae Blake (= Aster spinosus Benth.). The latter has been segregated as the monotypic Chloracantha (Nesom et al. 1991), while E. oxyphyllus has been treated as a member of the primarily Californian E. foliosus Nutt. group (Erigeron sect. Linearifolii = sect. Pycnophyllum, see Nesom & Noyes 1999). Batopilas (Erigeron) byei has no close similarity to any other species of Erigeron and does not fit into any previously circumscribed section (Nesom 1989; Noyes 2000). The small, few-flowered heads and the subterete, multinerved cypselae, in particular, are unusual in Erigeron, although no single morphological character is sufficient to exclude the species from the genus.

      The resemblance of Batopilasia to Chloracantha, as well as to the North American Boltonia, is conspicuous in their rhizomatous habit, reduced cauline leaves, persistently green-glabrate stems and leaves, erect buds, distinct phyllaries (thin-herbaceous, apically rounded to obtuse, with three, orange-resinous nerves), and deltate collecting appendages of the disc style branches. Chloracantha differs from Batopilasia primarily in vegetative features – taller stature, thick rhizomes, perennial, lignescent stems with thorns and axillary buds, lack of persistent basal leaves – but also in larger heads and greater number of flowers. The similarities of Batopilasia and Chloracantha in their subterete, 4–5-nerved cypselae and pappus of barbellate bristles are probably primitive (plesiomorphic), compared to Boltonia, in which the achenes are strongly flattened, winged, and reduced in pappus.

      Although its relatively generalized morphological features make it difficult to place the species within the tribe, DNA studies (Noyes & Rieseberg 1999) indicate that Batopilasia and Boltonia may be related as sister taxa (distant from Erigeron and relatives); other molecular studies (Suh 1989; Morgan 1990) suggest that Boltonia is closely related to Chloracantha.

 

references

 

Morgan, D.R. 1990. A systematic study of Machaeranthera (Asteraceae) and related groups using restriction site analysis of chloroplast DNA and a taxonomic revision of Machaeranthera section Psilactis. Ph.D. diss., Univ. of Texas, Austin.

Nesom, G.L. 1989. Infrageneric taxonomy of New World Erigeron (Compositae: Astereae). Phytologia 67:67–93.

Nesom, G.L., Y. Suh, D.R. Morgan, S.D. Sundberg, and B.B. Simpson. 1991. Chloracantha, a new genus of North American Astereae (Asteraceae). Phytologia 70:371–380.

Nesom, G.L. and R.D. Noyes. 1999. Notes on sectional delimitations in Erigeron (Asteraceae: Astereae). Sida 18:1161–1165.

Nesom, G.L. and R.D. Noyes. 2000. Batopilasia (Asteraceae: Astereae), a new genus from Chihuahua, Mexico. Sida 19(1), in press.

 Noyes, R.D. 2000. Biogeographical and evolutionary insights on Erigeron and allies (Asteraceae) from ITS sequence data. Pl. Syst. Evol. 220:93–114.

Noyes, R.D. and L.H. Rieseberg. 1999. ITS sequence data support a single origin of North American Astereae (Asteraceae) and reflect deep geographic divisions in Aster s.l. Amer. J. Bot. 86:398–412.

Suh, Y. 1989. Phylogenetic studies of North American Astereae (Asteraceae) based on chloroplast DNA. Ph.D. diss., Univ. of Texas, Austin.

Sundberg, S.D. and G.L. Nesom. 1990. A new species of Erigeron (Asteraceae: Astereae) from Chihuahua, Mexico. Phytologia 69:278–281.

 

13. BELLIS L., Sp. Pl. 886. 1753.

 

Annual or short-lived perennial herbs from fibrous roots, sometimes producing stolon-like rhizomes or offsets (as in B. perennis), the stem usually scapose (reduced-leafy in B. annua L.), 6–15 cm high. Leaves in a basal rosette, spatulate to obovate or oblanceolate, 2–7(–18) cm long, entire to shallowly toothed, sparsely pilose, sometimes continuing up the lower portion of the stem, alternate. Heads solitary; involucres shallowly cupulate, 3–8 mm high; phyllaries ovate or oval, evenly herbaceous, in (1–)2–3 even-length series; receptacle conic to hemispheric or nearly flat, folveolate. Ray florets pistillate, fertile, white above, often pinkish or purple-tinged beneath, closing upwards at night. Disc florets perfect, fertile, the corollas yellow, tubular with deltate, erect lobes, the tube very short, nearly stipe-like; style branches with deltate collecting appendages. Cypselae obovate, 1–1.5 mm long, strongly flattened, with 2, thick, marginal nerves, short-strigose or ciliate-margined to glabrous, sessile-glandular in B. azorica Hochst.; pappus absent or a crown of short bristles. Base chromosome number, x=9. (Latin, bellus, pretty.)

      Type species: Bellis perennis L.

      A genus of about eight species native to Europe, recognized by its leaves in a basal rosette, solitary heads on scapose stems, raised receptacles, short-tubed disc corollas, and flattened, obovate cypselae with pappus absent or reduced. Bellis perennis, the only species of the genus in North America, is introduced worldwide for its dimunitive beauty and has become a colonizer of disturbed areas, especially lawns and fields. It occurs mostly in the northern portion of North America and in cool localities in Mexico and Central America. Bellis was positioned within the monotypic subtribe Bellidinae (Nesom 1994), only slightly ameliorating the complete dissolution of the subtribe by DeJong (1965), but a position for Bellis in the Asterinae also is possible.

 

references

 

Carano, E. e V. Bambacioni. 1926. Richerche sul genere Bellis L., con speciale riguardo alla B. hybrida Ten. Annali de Botanica 16:9–70.

De Jong, D.C.D. 1965. A systematic study of the genus Astranthium (Compositae, Asteraeae). Michigan State Univ. Mus. Publ. Biol. Ser. 2: 429–528.

Mitich, L.W. 1997. Intriguing world of weeds. English daisy (Bellis perennis L.). Weed Technol. 11:626–628.

Murthy, H.N. 1988. Karyomorphological studies in Bellis perennis L. Cis (Chromosome Information Service) 45:3–4.

Nesom, G.L. 1994. Subtribal classification of the Astereae (Asteraceae). Phytologia 76:193–274.

Warwick, S.I. and D. Briggs. 1980. The genecology of lawn weeds. IV. Adaptive significance of variation in Bellis perennis L. as revealed in a transplant experiment. New Phytol. 85:275–288.

Webb, D.A. 1976. Bellis. Flora Europaea 4:111–112.

 

14. BENITOA Keck, Leafl. West. Bot. 8:26. 1956.

 

Annual, taprooted herbs, heavy-scented, viscid throughout with dark, tack-shaped glands, the stems 2–11 dm tall, sometimes reddish. Leaves glandular and often hirsute, linear-lanceolate to oblanceolate, entire, obtuse or acute, 4–9 cm long, 6–15 mm wide, narrowed to a clasping base, the upper becoming bract-like and apiculate. Heads terminal and on short lateral branches, forming a relatively diffuse, cymose-paniculate inflorescence; involucres cylindric-turbinate, 8–10 mm high, 3–5 mm wide; phyllaries linear, spreading or squarrose, each with a single, apical, tack-shaped gland. Ray florets 5–8(–14), fertile, the lamina broad, yellow, coiling at maturity. Disc florets 9–12, functionally staminate, with sterile ovaries, the corollas 4.5–5 mm long, markedly restricted at the throat; anthers borne on short filaments inserted at the tube-throat junction. Fertile cypselae maculate, lightly strigose, triangular in cross-section, 3.5–4 mm long, 3-nerved, with a greatly narrowed pappus insertion; pappus of 3–8 caducous bristles (sterile cypselae with shorter and fewer pappus members). Base chromosome number, x=5. (For San Benito County, California, where it occurs.)

      Type species: Benitoa occidentalis (H.M. Hall) Keck.

      A monotypic genus endemic to serpentine outcrops of the Diablo Range in a few west-central California counties (San Benito, Fresno, and Monterey) and characterized as densely viscid-glandular, narrow-leaved annuals with yellow-rayed heads, functionally staminate disc florets, triangular cypselae, and a few, caducous pappus bristles. Benitoa was segregated from Haplopappus and raised to generic rank by Keck (1956) but was recently submerged within Lessingia by Lane (1993a, 1993b), who emphasized similaries among Lessingia, Corethrogyne, and Benitoa. Each of these genera was maintained as distinct by Nesom (1994), who placed all three within the subtribe Machaerantherinae as the “Lessingia group.” In the original description of Benitoa, Keck noted similarities between it and Haplopappus sect. Blepharodon (= Machaeranthera) suggestive of a close relationship. Recent molecular studies (Morgan 1997) have confirmed the placement of the Lessingia group in the Machaerantherinae. As observed by Nesom (1994) on the basis of morphological characters, Lessingia and Corethrogyne appear to have a sister relationship; Benitoa is sister to the other two. This phyletic hypothesis was corroborated by molecular evidence (Lane et al. 1996), but Markos and Baldwin (submitted) find that Benitoa is more closely related to Hazardia than to Lessingia and Corethrogyne.

 

references

 

Hall, H.M. 1928. The genus Haplopappus – A phylogenetic study in the Compositae. Section 11. Isopappus. Carnegie Inst. Washington Publ. No. 389:35, 212–218.

Keck, D.D. 1956. Benitoa, a new genus of Compositae from California. Leafl. West. Bot. 8:25–28.

Lane, M.A. 1993a. New combinations in Californian Lessingia (Compositae: Astereae). Novon 3:213–214.

Lane, M.A. 1993b. Lessingia. Pp. 304–306 in J.C. Hickman (ed.). The Jepson manual: Higher plants of California. Univ. of California Press, Berkeley.

Lane, M.A., D.R. Morgan, Y. Suh, B.B. Simpson, and R.K. Jansen. 1996. Relationships of North American genera of Astereae, based on chloroplast DNA restriction site data. In D.J.N. Hind and H.J. Beentje (eds.). Compositae: Systematics. Vol. 1, pp. 49–77. Proc. Interntl. Compositae Conf., Kew, 1994.

Morgan, D.R. 1997. Reticulate evolution in Machaeranthera (Asteraceae). Syst. Bot. 22:599–615.

Nesom, G.L. 1994. Subtribal classification of the Astereae (Astereae). Phytologia 76:193–274.

Markos, S. and B.G. Baldwin. Submitted. Higher-level relationships and major lineages of Lessingia (Compositae, Astereae) based on nuclear rDNA internal and external transcribed spacer (ITS and ETS) sequences. Syst. Bot.

 

15. BIGELOWIA DC., Prodr. 5:326. 1836 (nom. conserv., Camp et al. 1947).

 

Chondrophora Raf., New Fl. N. Amer. 4:79. 1838.

 

Suffrutescent herbs from a short, fibrous-rooted caudex, colonial by short rhizomes or basal offsets, the stems 3–7 dm tall, glabrous, early viscid, often nearly scapose. Leaves in a persistent basal rosette, linear to oblanceolate, 4–14 cm long, 3-veined, sessile, entire, glandular-punctate, the cauline alternate, abruptly or progressively reduced upward, the upper linear and bracteate. Heads in a compact to open, terminal, distinctly flat-topped, corymboid inflorescence; involucres turbinate-cylindric to cylindric, 4.5–9 mm high; phyllaries narrowly lanceolate to nearly linear, weakly keeled, green-tipped, imbricate in 3–4 series, in more or less vertical ranks; receptacles alveolate. Ray florets absent. Disc florets 2–6, perfect, fertile, the corollas yellow, tubular, the lobes lanceolate and recurving; style branches with lanceolate collecting appendages. Cypselae turbinate to subcylindric, sometimes slightly compressed to nearly quadrate, 1–3.5 mm long, with 4–5, thin, resinous nerves, sparsely strigose; pappus of 1(–2) series of relatively few, barbellate bristles of uneven length. Base chromosome number, x=9. (For Massachusetts medical and botanical scholar Jacob Bigelow, 1787–1879, who published in 1814 the first local flora in North America, Florula Bostoniensis, which in later editions encompassed the northeastern United States.)

      Type species: Bigelowia nudata (Michx.) DC.

      A genus of two species, one with two varieties, essentially restricted to the southeastern United States (Anderson 1970, 1972b). Bigelowia is recognized by its leaves in basal rosettes or basally disposed, slender, nearly scapose stems, and flat-topped clusters of small, cylindric-turbinate, discoid heads with phyllaries in vertical ranks. Diploids, tetraploids, and hexaploids occur in B. nuttallii L. Anderson, although the polyploids are much more restricted in range than the diploids. Karyotypes of Bigelowia species, as well as various floral features, resemble those of Euthamia (Anderson 1970, 1972b), this hypothesis of relationship tentatively confirmed by the molecular evidence of Lane et al. (1996). Nesom (1994) placed Bigelowia closest to Chrysoma, Euthamia, Gundlachia, and Xylothamia within the Solidagininae on the basis of morphological evidence.

 

references

 

Anderson, L.C. 1970. Studies on Bigelowia (Astereae, Compositae). 1. Morphology and taxonomy. Sida 3:451–465.

Anderson, L.C. 1972a. Studies on Bigelowia (Asteraceae). II. Xylary comparisons, woodiness, and paedomorphosis. J. Arnold Arbor. 53:499–514.

Anderson, L.C. 1972b. Studies on Bigelowia (Asteraceae). III. Cytotaxonomy and biogeography. Syst. Bot. 2:209–218.

Camp, W.H., H.W. Rickett, and C.A. Weatherby. 1947. International rules of botanical nomenclature. Brittonia 6:1–120.

Lane, M.A., D.R. Morgan, Y. Suh, B.B. Simpson, and R.K. Jansen. 1996. Relationships of North American genera of Astereae, based on chloroplast DNA restriction site data. In D.J.N. Hind and H.J. Beentje (eds.). Compositae: Systematics. Vol. 1, pp. 49–77. Proc. Interntl. Compositae Conf., Kew, 1994.

Nesom, G.L. 1994. Subtribal classification of the Astereae (Asteraceae). Phytologia 76:193–274.

 

16. BOLTONIA L’Herit., Sertum Angl. 27. 1788 [1789].

 

Perennial, glabrous herbs from fibrous-rooted rhizomes or a short caudex, sometimes stoloniferous, with stems green and striate-ribbed, 3–20 dm tall. Leaves mostly cauline, alternate, entire, narrowly elliptic to oblanceolate or lanceolate, 3–15 cm long, sessile, sometimes decurrent. Heads pedunculate, few to numerous in an open corymb or diffuse, leafy panicle; involucres shallowly cupulate, 2–3.5 mm high; phyllaries in 2–4(–5) graduate or subequal series, narrowly oblong to lanceolate, with a thick, raised, and orangish midrib; receptacles convex to conical, relatively smooth. Ray florets ca. 20–60, pistillate, fertile, white to bluish, rarely pink. Disc florets yellow, perfect, fertile, cylindric, short-tubed and with conspicuous orange-resinous veins; style branches with deltate collecting appendages. Cypselae broadly elliptic to elliptic-obovate, 1–1.5 mm long, strongly flattened and broadly winged or unwinged, with a nerve at each margin, these often with conspicuous, orangish oil ducts, the faces sometimes minutely pubescent; pappus absent or a short corona, also with several small bristles and 2(–4) much longer, thickened, barbellate awns, these often reduced or absent on the ray cypselae. Base chromosome number, x=9. (For English botanist and artist James Bolton, ca. 1750s–1799.)

Lectotype species (Britton & Brown 1913): Boltonia glastifolia (J. Hill) L’Herit. (Boltonia asteroides (L.) L’Herit.).

      A genus of five species, all restricted to eastern North America and usually occurring in moist to wet habitats. Infraspecific variation in B. asteroides and B. diffusa has been studied in detail (Fernald 1940; Morgan 1966) but problems remain, particularly in characterization of infraspecific variation patterns. Anderson’s key to species (1987), adapted from Cronquist’s (1980), covers all of the species. Boltonia is recognized by its green stems, relatively few, persistent leaves, small, white-rayed heads, conical or convex receptacles, phyllaries with an orange-resinous midvein, short-tubed disc corollas, and flattened, eglandular, often winged cypselae with an abbreviated pappus.

      The history of inferred close relationship between Boltonia and the primarily Old World genus Kalimeris is summarized by Nesom (1994). Gu and Hoch (1997) concluded that these two genera are not closely related, and this has been confirmed by Noyes and Rieseberg (1999), who find that Boltonia is more closely related to Symphyotrichum and genera of the Machaerantherinae, all restricted in native distribution to the New World. Other morphological and molecular evidence suggests that Boltonia may be closely related to Batopilasia and Chloracantha (which see).

 

references

 

Anderson, L.C. 1987. Boltonia apalachicolensis (Asteraceae): a new species from Florida. Syst. Bot. 12:133–138.

Britton, N.L. and A. Brown. 1913. An illustrated flora of the northern United States, Canada, and the British Possessions (ed. 2). Vol. 3. Lancaster Press, Lancaster, Penn.

Cronquist, A. 1980. Boltonia. Pp. 168–169, in Vascular flora of the southeastern United States, Vol. I. Asteraceae. Univ. of North Carolina Press, Chapel Hill.

Fernald, M.L. 1940. A synopsis of Boltonia. Rhodora 42:482–492.

Gu, H. and P.C. Hoch. 1997. Systematics of Kalimeris (Asteraceae: Astereae). Ann. Missouri Bot. Gard. 84:762–814.

Morgan, J.T. 1966. A taxonomic study of the genus Boltonia (Asteraceae). Ph.D. diss., Univ. of North Carolina, Chapel Hill.

Nesom, G.L. 1994. Review of the taxonomy of Aster sensu lato (Asteraceae: Astereae), emphasizing the New World species. Phytologia 77:141–297.

Noyes, R.D. and L.H. Rieseberg. 1999. ITS sequence data support a single origin of North American Astereae (Asteraceae) and reflect deep geographic divisions in Aster s.l. Amer. J. Bot. 86:398–412.

Schwegman, J.E. and R.W. Nyboer. 1985. The taxonomic and population status of Boltonia decurrens (Torr. & Gray) Wood. Castanea 50:112–115.

Smith, M. and T.M. Keevin. 1998. Cypsela morphology, production and germination, and potential for water dispersal in Boltonia decurrens (decurrent false aster), a threatened floodplain species. Rhodora 100:69–81.

 

17. CALLISTEPHUS Cass., Dict. Sci. Nat. 37:491. 1825 (nom. conserv.).

 

Callistemma Cass., Bull. Sci. Soc. Philom. Paris 1817:32. 1817 (nom. rejec.).

Asteriscodes O. Kuntze, Rev. Gen. 1:318. 1891.

 

Annual, erect, sparingly branched herbs ca. 3–8 dm high, from a short taproot, the stems pilose-hirsute. Leaves mostly cauline, eglandular, the lamina glabrous to sparsely strigose, margins sparsely ciliate, the basal and lower cauline sometimes not persistent, the cauline 6–14 cm long, with broadly ovate to triangular-ovate blades, coarsely incised or toothed and tapered to a broad, non-clasping petiole, gradually reduced upward, the upper becoming spatulate and epetiolate, narrower, and more shallowly toothed. Heads terminal on leafy peduncles, solitary or few in a loosely paniculate or corymboid arrangement; involucres hemispheric, ca. 10–25 mm high, 2–9 cm wide; outer phyllaries in 2–3(–5) series, foliaceous, 10–30 mm long, oblong-spatulate, long-ciliate on at least the lower 2/3 of the margins, usually spreading, the inner in 1–2 series, membranous-scarious, often white, lightly veined, broadest at or near the apex, slightly shorter than the outer or nearly equal; receptacles flat to slightly convex, foveolate. Ray flowers pistillate, fertile, numerous in 1–2 series (wild types; to many series in cultivars), the ligules 1.5–3(–5.5) cm long, blue, purple, red, violet, lilac, pink, or white; cultivars commonly with disc flowers transformed into numerous extra series of ray-like outer flowers of variable size and shape. Disc flowers perfect, yellow, symmetric, short-tubed at the base, abruptly ampliate into the limb, the 5 lobes lanceolate to deltate-lanceolate, erect to spreading; style branches with deltate to broadly lanceolate collecting appendages. Achenes oblong-obovate, 3.5–5 mm long, flattened, with 2 lateral, narrow but thickened nerves, densely to moderately strigose-sericeous, eglandular; pappus of an inner series of basally caducous barbellate bristles 4–7 mm long and a short outer series of bristles or squamae. Base chromosome number, x=9. (Greek, kallos, beauty, stephanos, wreath or crown; Cassini (Dict. 6S:46. 1817) noted that the name referred to the “belle couronne,” surely in reference to the beautiful, crown-like flowering heads prized by gardeners rather than to the pappus, as surmised or repeated by various authors.)

      Type species: Aster chinensis L. (= Callistemma hortensis Cass. = Callistephus chinensis (L.) Nees).

      Cassini described the genus Callistemma in 1817 but noted in 1825 that the name was preoccupied by an earlier homonym of Robert Brown and provided Callistephus as a nomen novum. Brown’s Callistemon (Myrtaceae) of 1814, however, is different in spelling and etymology and Callistemma Cass. is not illegitimate. Even so, Callistephus Cass. has been formally conserved over Callistemma Cass. In the original description of Callistemma, Cassini explicitly cited Aster chinensis L. as the type but promptly (Dict. Sci. Nat. 6(Suppl.):46. 1817) renamed the species Callistemma hortensis Cass., using his own generic name and a substitute epithet. The currently accepted combination, Callistephus chinensis (L.) Nees, was made by C.G.D. Nees (Gen. Sp. Aster. 222. 1832).

      A monotypic genus native at least to northern China (provinces of Hopei, Shansi, Kirin, Heilungkiang, and Chahar – Hu 1968). It was noted to occur in “E. Mongolia, Manchuria, N. Korea, & N. China” by Kitagawa (1979). Attributions of its native occurrence in Japan are not corroborated by Meyer and Walker (1965). It is grown in temperate regions world-wide as a garden plant, valued for its Chrysanthemum-like flowers, and notes on its cultivation are given in various books (e.g., Everett 1981). Early cultivars, including various colors, were grown in France as early as the 1730s and “doubles” were in gardens there by the 1750s (Fisher 1982). The species apparently escapes from cultivation, although hardly becoming common or strongly naturalized. It has been recorded as growing outside of cultivation in North America from Connecticut, Maine, Michigan, New York, Pennsylvania, and Wisconsin (Kartesz 1999).

      As originally recognized and described by Cassini, Callistephus is distinguished from Aster and close relatives by its double pappus (with an outer series of short bristle-like squamellae) and particularly by the involucre (the outer bracts foliaceous, the innermost white-scarious); Cassini noted in 1825 that the outer, foliaceous members of the involucre might better be considered bracts surrounding the true involucre. Callistephus apparently has generally been regarded as so distinct among Asian species of Aster that it has rarely been included in considerations of relationships among these species and segregate genera. A connection between Callistephus, Heteropappus, and Kalimeris, however, was early recognized: Heteropappus hispidus (Thunb.) Less. was placed in Callistephus by de Candolle as C. biennis (Ledeb.) Lindl. ex DC. (Prodr. 5:274. 1836) and in Kalimeris by Nees as K. hispidus (Thunb.) Nees (Gen. Sp. Ast. 227. 1832).

      Callistephus shares distinctive features with other genera of the “Kalimeris group” (sensu Nesom 1994 – Kalimeris Cass., Heteropappus Less., Miyamayomena Kitam., and Callistephus): leaves with coarsely toothed or lobed margins, heads on leafy branches in a loosely organized inflorescence, convex receptacles, short-tubed disc corollas, and a tendency for a reduced or caducous pappus. Gu and Hoch (1997) observed that Heteropappus and Aster sect. Ageratoides (Kitam.) Nesom are the groups most similar to Kalimeris. Kalimeris, Heteropappus, and sect. Ageratoides appear as discrete subgroups of a monophyletic clade in cpDNA studies (Ito et al. 1994, 1995). In the limited Old World sampling of Noyes and Rieseberg’s phylogenetic analysis (1999), Asian Aster and Kalimeris appear as sister taxa. Generic boundaries among these putatively generic-level taxa, including Callistephus, need to be examined in more detail and in a broader context of their relationships to other Asian groups of Aster s. lat.

 

references

 

Everett, T.H. 1981. The New York Botanical Garden illustrated encyclopedia of horticulture. Vol. 2, Be–Cha. Garland Publishing, Inc., New York.

Fisher, J. 1982. The origins of garden plants. Constable and Co., Ltd., London.

Gu, H. 1989. On chromosome numbers of Kalimeris (Astereae, Asteraceae) and some related taxa. Cathaya 1:1–16.

Gu, H. and P.C. Hoch. 1997. Systematics of Kalimeris (Asteraceae: Astereae). Ann. Missouri Bot. Gard. 84:762–814.

Hu, S-Y. 1968. Callistephus. The Compositae of China (VI). Quart. J. Taiwan Mus. 19(1&2):11–12.

Ito, M., A. Soejima, and T. Nishino. 1994. Phylogeny and speciation of Asian Aster. Korean J. Pl. Taxon. 24:133–143.

Ito, M., A. Soejima, M. Hasebe, and K. Watanabe. 1995. A chloroplast-DNA phylogeny of Kalimeris and Aster, with reference to the generic circumscription. J. Pl. Research 108:93–96.

Kartesz, J.T. 1999. A synonymized checklist and atlas with biological attributes for the vascular flora of the United States, Canada, and Greenland. First Edition. In Kartesz, J.T., and C.A. Meacham. 1999. Synthesis of the North American flora, Version 1.0. North Carolina Botanical Garden, Chapel Hill.

Kitagawa, M. 1979. Neo-lineamenta florae manshuricae, or, Enumeration of the spontaneous vascular plants hitherto known from Manchuria (north-eastern China) together with their synonymy and distribution. J. Cramer, Vaduz, Liechtenstein.

Meyer, F.G. and E.H. Walker (eds.). 1965. Flora of Japan (in English), a combined, much rev., and extended translation of J. Oi’s Flora of Japan (1953) and Flora of Japan, Pteridophyta (1957). Smithsonian Institution, Washington, D.C.

Nesom, G.L. 1994. Review of the taxonomy of Aster sensu lato (Asteraceae: Astereae), emphasizing the New World species. Phytologia 77:141–297.

Noyes, R.D. and L.H. Rieseberg. 1999. ITS sequence data support a single origin of North American Astereae (Asteraceae) and reflect deep geographic divisions in Aster s.l. Amer. J. Bot. 86:398–412.

 

18. CALOTIS R. Br., Bot. Reg., t. 504. 1820.

 

Huenefeldia Walp., Linnaea 14:307. 1840.

Goniopogon Turcz., Bull. Soc. Nat. Mosc. 24:173. 1851.

Cheiroloma F. Muell., Linnaea 25:401. 1852.

Tolbonia O. Kuntze, Rev. Gen. Pl. 1:369. 1891.

 

Annual or perennial herbs, occasionally subshrubs, prostrate to ascending or erect, 5–90 cm high, sometimes stoloniferous, glabrate to hispid or hirsute. Leaves cauline and/or basal, alternate, oblong, lanceolate or oblanceolate, to cuneate or spatulate, 0.5–10(–24) cm long, petiolate or sessile, sometimes clasping, flat, the margins usually toothed or pinnately lobed. Heads solitary or in loose, leafy cymes, few to numerous, terminal or axillary, pedunculate to nearly sessile, involucres campanulate to nearly globose, ca. 2.5–5.5 mm high; phyllaries herbaceous, in 2–3(–4) series; receptacle flat to rounded or conic, sometimes with small scales. Ray florets pistillate, in 1-several series, the lamina blue or purple to white or yellow, sometimes minute. Disc florets bisexual but usually with sterile ovaries (fertile in C. hispidula (F. Muell.) F. Muell.), yellow, short-tubed and abruptly expanded into the limb, the lobes deltate-lanceolate, erect to spreading; style branches with deltate collecting appendages. Cypselae cuneate or obconic, 0.8–4 mm long, flattened or angled, sometimes winged, glabrous or strigose, the faces sometimes tuberculate; pappus of (1–)2–25 rigid, equal to subequal, erect to spreading awns, often retrorsely barbed at least toward the apex, sometimes ciliate, sometimes the awns basally dilated and united, commonly alternating with low scales, rarely absent, the pappus of 12–15 short-plumose bristles in C. inermis Maiden & Betche. Base chromosome number, x=8, reduced to x=7, 5, and 4.

      Type species: Calotis cuneifolia R. Br.

      A genus of ca. 28–30 species, most native to Australia (Davis 1952; Cooke 1985; Short 1991); two are from southeast Asia (see comments in Nesom 1994). Calotis cuneifolia was reported for Massachussetts by Sorrie (1989) but there is no evidence that it has persisted as a naturalized element in the North American flora. The species has become naturalized outside its native range, however, in temperate climates. The greatest species diversity in Calotis occurs in arid and semiarid regions of eastern Australia. In addition to the well-documented, descending dysploid series, polyploidy occurs in at least half of the species, and at least one agamic complex involving polyploidy is known (Stace 1978).

      Plants of Calotis are recognized by their primarily herbaceous habit, solitary or loosely aggregated heads, disc florets with short-tubed corollas and sterile ovaries, and cuneate cypselae, often with tuberculate faces and usually with a pappus of retrorsely barbed awns and shorter series of scales. The cypselae vary greatly in shape, winging, and the elaboration of awns and scales. The rays vary among species from yellow to white, purple, and blue. The heads in some species become subglobose at maturity with protruding barbed awns, hence the common name “bur daisy.” The elliptic-obovate cypselae and thin pappus elements of C. inermis are unusual, although Stace (1978) placed the species with other more typical ones within his “Group I.” Calotis was positioned (Nesom 1994) with Brachyscome Cass. and Ceratogyne Turcz. as a member of the subtribe Brachyscominae.

 

references

 

Asai, Y. 1988. Additional notes on Calotis cuneifolia in Japan. J. Japan. Bot. 63:14.

Cooke, D.A. 1985. Studies in the tribes Astereae and Inuleae (Compositae). J. Adelaide Bot. Gard. 7:273–287.

Davidson, J.K. and H.M. Stace. 1986. Genetics of self-incompatibility in Calotis cuneifolia. J. Hered. 77:471–472.

Davis, G.L. 1952. Revision of the genus Calotis R. Br. Proc. Linnaean Soc. New South Wales 77:146–188.

Nesom, G.L. 1994. Subtribal classification of the Astereae (Asteraceae). Phytologia 76:193–274.

Sharma, B.M. and P.S. Jamwal. 1984. Genus Calotis an addition to the Indian Asteraceae. Indian J. Forestry 7:333–334. [Calotis hispidula]

Short, P.S. 1991. A new species of Calotis R. Br. (Asteraceae: Astereae) from New South Wales. Muelleria 7:405–410.

Sorrie, B.A. 1989. County checklist of Massachusetts plants. Unpublished manuscript, submitted to The Nature Conservancy.

Stace, H.M. 1978. Cytoevolution in the genus Calotis R. Br. (Compositae: Astereae). Austral. J. Bot. 26:287–307.

 

19. CANADANTHUS Nesom, Phytologia 77:250. 1994.

 

Aster subg. Canadanthus (Nesom) Semple, Univ. of Waterloo Biol. Ser. 38:36. 1996.

 

Perennial, thin-rhizomatous herbs, the stems simple and arising singly from the base, 3–8 dm tall, with abundant long-stipitate glands. Leaves all cauline, eglandular, glabrate to thinly short-strigose above, loosely and thinly pilosulous beneath, epetiolate, subclasping, lanceolate to elliptic-lanceolate with an acuminate apex, entire to shallowly serrate, 5–12 cm long, the lowermost strongly reduced in size. Heads mostly 3–20 on leafy peduncles, loosely corymboid, less commonly solitary, sometimes many more and the inflorescence thyrsoid; involucres broadly turbinate to hemispheric, 7–10 mm high; phyllaries linear-lanceolate, in 2–3 series of nearly equal length, thin-herbaceous, stipitate-glandular, without a green apical patch or indurated basal region, the inner often with a slightly raised keel and usually strongly purplish; receptacle without chaff. Ray florets pistillate, fertile, 25–40 with purple, coiling lamina. Disc florets perfect, fertile, the corollas narrowly tubular with short, erect lobes; style branches with triangular, hairy collecting appendages. Cypselae oblanceolate with a narrowly acute, stipitate base, 2.5–4 mm long, strongly flattened, 4–8 nerved, eglandular; pappus of 1(–2) series of apically attenuate barbellate bristles. Base chromosome number, x=9. (Canada, and Greek, anthos, flower, in reference to the primarily Canadian distribution of the species.)

      Type species: Canadanthus modestus (Lindl.) Nesom.

      A monotypic genus occurring from Alaska, Yukon, and British Columbia and across the Canadian provinces to New Brunswick, southward into Washington, Oregon, Idaho, and Montana and in Minnesota and Michigan. Data of Xiang and Semple (1993) indicate that western US population systems of the species are genetically differentiated from those in northwestern Ontario. Canadanthus is characterized by its stipitate-glandular vestiture, clasping cauline leaves, purple rays, linear, even-length, and herbaceous phyllaries, oblanceolate, flattened cypselae with a 1–2-seriate pappus, and base chromosome number of x=9. The heads are borne on leafy peduncles in a loose corymb, more like inflorescences found in Symphyotrichum (particularly S. novae-angliae) than in Eurybia, Oclemena, or other putatively primitive genera with a distinctly corymboid inflorescence (Nesom 1994). The molecular phylogenetic analysis of Xiang and Semple (1996) indicates that the evolutionary origin of Canadanthus lies near the base of Symphyotrichum, and they informally suggest that Canadanthus should be included within the latter. A combination of morphological and chromosomal features separates Canadanthus from Symphyotrichum subg. Virgulus: leaves relatively broad, thin, and toothed (vs. narrow, thick, and entire), phyllaries completely without an apical patch, stems arising singly from the base, cypselae strongly flattened, pappus tending to be 2-seriate, and chromosome number 2n=18.

 

references

 

Nesom, G.L. 1994. Review of the taxonomy of Aster sensu lato (Asteraceae: Astereae), emphasizing the New World species. Phytologia 77:141–297.

Xiang, C. and J.C. Semple. 1993. RAPD study of Aster modestus (Compositae: Astereae). [Abstract] Amer. J. Bot. 80(6):184.

Xiang, C. and J.C. Semple. 1996. Molecular systematic study of Aster s. lat. and related genera (Asteraceae: Astereae) based on chloroplast DNA restriction site analyses and mainly North American taxa. In D.J.N. Hind and H.J. Beentje (eds.). Compositae: Systematics. Vol. 1, pp. 393–423. Proc. Interntl. Compositae Conf., Kew, 1994.

 

20. CENTIPEDA Lour., Fl. Cochinch. 492. 1790.

 

 Cotula sect. Centipeda (Lour.) Baill., Hist. Pl. 8:284. 1882.

Myriogyne Less., Linnaea 6:219. 1831 (apparently untypified).

 

Annual or perennial, taprooted, sessile-glandular, otherwise glabrous to arachnoid-tomentose herbs with equably leafy, procumbent to erect, basally branched stems, 5–20 cm high. Leaves alternate, simple, petiolate or epetiolate, linear to lanceolate, spatulate to spatulate-oblong, or obovate, 4–15(–20) mm long, entire to variously toothed or lobed, sessile-glandular at least on the lower surfaces. Heads disciform, solitary and axillary, sessile or short-peduncled, or in short, terminal racemes; involucres hemispheric, 1–4 mm high, 2–8 mm wide; phyllaries obovate, apically rounded, in 2–4 subequal to graduate series, thin-herbaceous with hyaline margins; receptacle convex, without chaff. Rays florets pistillate, fertile, in ca. 2–8 series, minute, filiform-tubular and eligulate, whitish, shorter than the involucre. Disc florets 10–30, perfect, fertile, the corollas yellow, tubular-funnelform, short-tubed, with 4, deeply cut, erect to flaring lobes; style branches with truncate to barely deltate collecting appendages. Cypselae oblong-obovoid to cylindric, (3–)4(–6)-angled/ribbed, thickened at the apex, 1–3 mm long, hirsute along the angles, the trichomes glochidiate in C. cunninghamii (DC.) A. Braun & Aschers., usually sparsely sessile-glandular; pappus absent but the cypsela summit sometimes extended into a shallow, hyaline or cartilaginous rim. Base chromosome number, x=10. (Latin, centum, a hundred, pes or pedis, foot, referring to the many spreading branches.)

      Type species: Centipeda orbicularis Lour. (= Centipeda minima (L.) A. Braun & Aschers.).

      A genus of five species in tropical Asia (one species; e.g., Chu & Gou-Xun 1983; Li 1978) and Australia and New Zealand (three species; e.g. Brown 1992, Webb et al. 1988), with one native in South America. Centipeda elatinoides (Less.) Benth. & Hook. ex Hoffm. is endemic to south Chile and Neuquen Province in west-central Argentina (Cabrera 1971). Centipeda minima apparently is the only species of the genus with weedy tendencies – it is native to southeast Asia (Japan, China, Taiwan, Okinawa and associated islands), and perhaps to Australia and New Zealand, and it has been naturalized in other areas of the world. It occurs in Afghanistan and “throughout the plains of India and Ceylon” (Hooker 1882) and in open fields in Nepal (Malla et al. 1986). Centipeda minima has been reported as locally common on “waste lands and roadsides,” “wet soil in paddy field and on stream banks,” “floodplains and damp areas,” “roadsides,” “margins of lakes, ponds, and streams, swamps and waste places.” Centipeda cunninghamii has recently been recorded from Europe (Sanchez R. & Elias R. 1998).

      Centipeda is represented in North America by one adventive species. Centipeda minima has been recorded in the northeastern United States in Massachussetts “among strawberry plants just outside the botany greenhouses of Wellesley College” (Ottley 1938) and in Pennsylvania (Fernald 1950). The species presumably has not persisted at these sites or spread. It was not recorded for the Pennsylvania flora by Rhoads and Klein (1993); it was excluded from the Massachusetts flora by Sorrie (1989), who noted that “no specimen [was] seen.”

      Centipeda is characterized by glandular-resinous herbage, pauciseriate, subequal phyllaries, multiseriate, eligulate pistillate florets and relatively few disc florets, glandular, 3–6 ribbed, obovoid, essentially epappose cypselae, and base chromosome number of x=10. All species grow in damp habitats or sites prone to periodic flooding. In a review of its features, the genus was positioned in the subtribe Grangeinae by Nesom (1994), emphasizing similarities to Egletes. This is in agreement with Bremer and Humphries (1993), but Centipeda has most often been placed in the Anthemideae. Several features unusual for the Astereae indicate that placement in that tribe remains tentative, particularly the chromosome number and the description of plants as “aromatic” (e.g., Webb et al. 1988). The multiseriate, graduate phyllaries with white-hyaline margins of C. thespidioides F. Muell. suggest that it is out of place within Centipeda.

      Chromosome counts of 2n=20 have been reported for Centipeda minima (Nishikawa 1985; Gupta & Gill 1989), apparently reflecting a base chromosome number either of x=5 or x=10. In either case the number is specialized within the Grangeinae, which otherwise is consistently x=9. If the base number is x=10, it is the only genus in the Astereae with that number.

 

references

 

Cabrera, A. 1971. Flora Patagonica. Parte VII. Compositae. Colleciσn Cientifica del INTA, Buenos Aires, Argentina.

Bremer, K. and C.J. Humphries. 1993. Generic monograph of the Anthemideae (Astereae). Bull. Nat. Hist. Mus. London (Bot.) 23(2):71–177.

Brown, E.A. 1992. Centipeda. In G.J. Harden (ed.), Flora of New South Wales 3:293–294.

Fernald, M.L. 1950. Gray’s Manual of Botany (ed. 8). American Book Company, New York.

Gupta, R.C. and B.S. Gill. 1989. Cytopalynology of north and central Indian Compositae. J. Cytol. Genet. 24:96–105.

Hooker, J.D. 1882. Centipeda. Flora of British India 3:317.

Li, H. 1978. Centipeda. Flora of Taiwan 4:821–823.

Malla, S.B. et al. (eds.). 1986. Flora of Kathmandu Valley. Ministry of Forests and Soil Conservation, Kathmandu, Nepal.

Nesom, G.L. 1994. Subtribal classification of the Astereae (Asteraceae). Phytologia 76:193–274.

Nishikawa, T. 1985. Chromosome counts of flowering plants of Hokkaido (9). J. Hokkaido Univ. Educ., Sect. 2B 36:25–40.

Ottley, A.M. 1938. The occurrence of Centipeda minima in Wellesley, Massachussetts. Rhodora 40:219–220.

Rhoads, A.F. and W.M. Klein, Jr. 1993. The vascular flora of Pennsylvania: Annotated checklist and atlas. Amer. Philosophical Soc., Philadelphia, Penn.

Sanchez Rodriguez, J.A. and M.J. Elias Rivas. 1998. Centipeda cunninghamii (DC.) A. Braun et Ascherson (Asteraceae), una planta adventicia nueva para Europe. An. Jard. Bot. Madrid 56:167.

Shih Chu and Fu Gou-Xun. 1983. Flora Reipublicae Popularis Sinicae, Compositae (3), [Anthemideae]. Tomus 76:1–149.

Sorrie, B.A. 1989. County checklist of Massachusetts plants. Unpublished manuscript submitted to The Nature Conservancy.

Webb, C.J., W.R. Sykes, and P.J. Garnock-Jones. 1988. Centipeda. Flora of New Zealand 4:164–165.

 

21. CHAETOPAPPA DC., Prodr. 5:301. 1836.

 

Leucelene Greene, Pittonia 3:147. 1896.

 

Annual or perennial herbs, the stems erect or decumbent 5–30 cm tall. Leaves alternate, simple, entire, oblanceolate-obovate to spatulate,10–75 mm long. Heads solitary and terminal, not crowded; involucres turbinate-cylindric to hemispheric; involucres broadly conic to hemispheric, 3.8–6.5 mm high; phyllaries elliptic to linear-lanceolate, in 2–6 graduated series, with wide, prominent, whitish-scarious margins; receptacle without chaff, flat or slightly convex. Ray florets 6–20, pistillate, fertile, the lamina usually white, drying white to blue or purple, coiling at maturity. Disc florets perfect, fertile but the central ones sometimes with sterile ovaries, the corollas yellow, tubular, regular; style appendages shallowly triangular to narrowly triangular. Cypselae terete to strongly compressed, 2–5–, 8–, or 10-nerved, 1.3–2.8 mm long, sparsely strigose, sessile-glandular in some species; pappus of a hyaline crown, hyaline scales, awn-like bristles, or a combination of alternating scales and bristles, the members usually 5 or a multiple of 5, or reduced to a minute crown and appearing essentially absent. Base chromosome number, x=8. (Greek, chaite, long hair, and pappus.)

      Type species: Chaetopappa asteroides (Nutt.) DC.

      A genus of 11 species restricted to northern Mexico and the south-central USA. The genus is recognized by its entire leaves, graduated phyllaries with sharply delimited, white-scarious margins, and small heads with white or bluish, coiling rays. Included within Chaetopappa is Leucelene (see Nesom, 1988), which traditionally has been considered a separate genus because of its entirely capillary pappus. Chaetopappa plomoensis Turner, however, which is otherwise closely similar to the bristleless C. parryi A. Gray, also has a pappus of only bristles. The Texas endemic C. bellioides (A. Gray & Engelm.) Shinners is completely without a pappus or produces only a minute crown.

      Keck (1958) considered the species of Pentachaeta (essentially Californian in distribution) to be congeneric with Chaetopappa, but Van Horn (1973) maintained the two as separate genera. One other species from New Mexico recently described as Chaetopappa has been transferred to the genus Ionactis (Nesom 1992), with the clarification of apparent inconsistencies in the base chromosome number of Chaetopappa.

 

references

 

Greene, E.L. 1896. Studies in the Compositae. – IV. Pittonia 3:146–149.

Keck, D.D. 1958. Taxonomic notes on the California flora. Aliso 4:101–114.

Nesom, G.L. 1988. Synopsis of Chaetopappa (Compositae: Astereae) with a new species and the inclusion of Leucelene. Phytologia 64:448–456.

Nesom, G.L. 1992. Transfer of Chaetopappa elegans to Ionactis (Asteraceae: Astereae). Phytologia 73:416–424.

Shinners, L.H. 1946a. Revision of the genus Chaetopappa. Wrightia 1:63–81.

Shinners, L.H. 1946b. Revision of the genus Leucelene Greene. Wrightia 1:82–89.

Van Horn, G.S. 1973. The taxonomic status of Pentachaeta and Chaetopappa with a revision of Pentachaeta. Univ. of California Publ. Bot. 65:1–41.

 

22. CHLORACANTHA Nesom, Suh, Morgan, Sundberg, & Simpson, Phytologia 70:378. 1991.

 

Aster sect. Spinosi (Alexander) A.G. Jones, Brittonia 32:233. 1980.

Erigeron sect. Spinosi (Alexander) Nesom & Sundberg, Phytologia 67:85. 1989.

 

Glabrous or glabrate, glaucous, perennial subshrubs forming large clones, spreading by stout rhizomes, the main stems strictly erect, 0.5–1.5(–2.5) m tall, with lateral branches sharply ascending, the latter sometimes modified as thorns. Leaves all cauline, alternate, 1-nerved, mostly 1–4 cm long, oblanceolate, entire or very rarely with 1–2 pairs of small teeth, early deciduous, nearly glabrous. Heads produced singly in loose, corymboid panicles; involucres broadly turbinate to hemispheric, 4.5–7.5 mm long; phyllaries graduated in 4–5 series, each with (1–)3(–5), parallel, orange-resinous veins, oblong-elliptic to lanceolate, with rounded to lanceolate apices and hyaline margins; receptacles shallowly convex, epaleate. Ray florets 10–33, pistillate, fertile, the corollas white, coiling at maturity. Disc florets perfect, fertile, the corollas yellow with orange-resinous veins, narrowly funnelform, the lobes deltate; style branches with deltate to triangular collecting appendages. Cypselae glabrous, slightly compressed, 1.5–3.5 mm long, 5(–6)-nerved; pappus of barbellate bristles in 1–2 series, usually with a few much shorter outer setae. Base chromosome number, x=9. (Greek, chloros, green, akantha, thorn.)

      Type species: Chloracantha spinosa (Benth.) Nesom.

      A monotypic genus comprising four varieties, which range from Central America (Panama to Guatemala) through Mexico and into the southwestern USA from southern California as far north as southern Utah and east to Oklahoma, Texas, and southwestern Louisiana. The plants quickly lose their leaves and become masses of upright, stout to thin, green stems with loose panicles of small, terminal, white-rayed heads producing small cypselae with a 1–2 seriate pappus of bristles. Two of the southern varieties are heavily thorny. Only var. spinosa occurs in the USA; it may be thorny at the base but armament of the upper portions is variable among populations, with some producing only thornless, wand-like branches. The plants occur in a variety of habitats near water, mostly at low elevations but at some sites up to nearly 2000 m. They flower June through October in the northern part of the range but nearly all year in the south. Geographic variation within Chloracantha spinosa has been studied in detail by Sundberg (1991), who provided a treatment of its infraspecific taxonomy and discussions of problems in typification.

      Although Chloracantha spinosa produces no terminal resting buds and its permanently green stems without periderm are herbaceous in aspect, it behaves more like a shrub in its perennial stems (alive for up to about four growing seasons) with a quickly developed vascular cambium and its production of axillary buds with bud scales. All or almost all of the leaves are usually shed by flowering. Such a distinctive growth form is not known in Aster or Erigeron, the two genera with which the species has been allied, or in any other potentially closely related taxa (Nesom et al. 1991). Studies of restriction site variation in chloroplast DNA have indicated that C. spinosa and the genus Boltonia may be closely related (studies by Youngbae Suh and by David Morgan, summarized in Nesom et al. 1991).

 

references

 

Nesom, G.L., Y. Suh, D.R. Morgan, S.D. Sundberg, and B.B. Simpson. 1991. Chloracantha, a new genus of American Astereae (Asteraceae). Phytologia 70:371–381.

Sundberg, S.D. 1991. Infraspecific classification of Chloracantha spinosa (Benth.) Nesom (Asteraceae) Astereae. Phytologia 70:382–391.

 

23. CHRYSOMA Nutt., J. Acad. Nat. Sci. Philadelphia 7:67. 1834.

 

Evergreen shrubs 0.5–1 m tall, glabrous, glutinous. Leaves alternate, oblanceolate to narrowly-elliptic, 2–6 cm long, 2–10 mm wide, entire, sometimes tapered to a short petiolar portion, sessile, 1-nerved, covered by a reticulum of subisodiametric areoles, each areole surrounded by a sunken border that appears to be the source of a resinous exudate. Heads sessile to subsessile in dense, terminal, cymose clusters; involucres cylindric, 5–6 mm high, glutinous; phyllaries lanceolate, stramineous, with an orange-resinous midvein from base to apex, imbricate in 3–4(–5) series and aligned in vertical rows; receptacle shallowly alveolate. Ray florets 1–2(–3) or sometimes absent, the lamina 4–6 mm long. Disc florets (2–)3–4(–5), perfect, fertile, tubular and greatly elongated, 4.5–5 mm long, without a sharp tube-limb transition, the lobes lanceolate and spreading-recurving; style branches with linear-triangular, papillate collecting appendages. Cypselae turbinate-oblong, 2.5–3 mm long, with 8–10 raised, whitish nerves, densely strigose-sericeous; pappus of 2–3 series of barbellate bristles of uneven length. Base chromosome number, x=9. (Greek, chrysos, gold, -ome, having the condition of, referring to the predominantly yellow-gold heads and corymbs.)

      Type species: Chrysoma solidaginoides Nutt. (= Chrysoma pauciflosculosa (Michx.) Greene).

      A monotypic genus endemic to the Atlantic and Gulf coastal plain, originally described by Michaux as a species of Solidago and often treated as such but highly distinctive in its anatomy (Lloyd 1901; Phillips 1963; Anderson and Creech 1975). With its strongly corymboid inflorescence of glomerate, cylindric, few-flowered heads, long disc corolla lobes, and papillate collecting appendages of the disc style branches, it is a member of subtribe Solidagininae and hypothesized by Nesom (1991, 1993) to be closely related to Euthamia, Bigelowia, and Gundlachia. Molecular data of Zhang (1996), illustrated by Semple et al. (1999), suggest that Chrysoma is the sister group to a clade comprising Oreochrysum, Oligoneuron, and Solidago. Illustrations of habit and details for Chrysoma pauciflosculosa are provided in Godfrey (1988).

 

references

 

Anderson, L.C. and J.B. Creech. 1975. Comparative leaf anatomy of Solidago and related Asteraceae. Amer. J. Bot. 62:486–493.

Cronquist, A. 1980. Chrysoma. P. 134 in Vascular flora of the southeastern United States, Vol. I. Asteraceae. Univ. of North Carolina Press, Chapel Hill.

Godfrey, R.K. 1988. Trees, shrubs, and woody vines of northern Florida and adjacent Georgia and Alabama. Univ. of Georgia Press, Athens.

Greene, E.L. 1895. Observations on the Compositae.– VIII. Erythea 3:6–15.

Kapoor, B.M. and J.R. Beaudry. 1966. Studies on Solidago. VII. The taxonomic status of the taxa Brachychaeta, Brintonia, Chrysoma, Euthamia, Oligoneuron, and Petradoria in relation to Solidago. Canad. J. Genet. Cytol. 8:422–443.

Lloyd, F.E. 1901. Some points in the anatomy of Chrysoma pauciflosculosa. Bull. Torrey Bot. Club 28:445–450.

Nesom, G.L. 1991. Morphological definition of the Gutierrezia group (Asteraceae: Astereae). Phytologia 71:252–262.

Nesom, G.L. 1993. Taxonomic infrastructure of Solidago and Oligoneuron (Asteraceae: Astereae) and comments on their phylogenetic position. Phytologia 75:1–44.

Nuttall, T. 1834. A description of some of the rare or little known plants indigenous to the United States. J. Acad. Nat. Sci. Philadelphia 7:61–115.

Phillips, K. 1963. A taxonomic and morphological study of Chrysoma pauciflosculosa (Michx.) Greene. M.S. Thesis, Univ. of South Carolina, Columbia.

Semple, J.C., G.S. Ringius, and J.J. Zhang. 1999. The goldenrods of Ontario: Solidago L. and Euthamia Nutt. (ed. 3). Univ. of Waterloo Biol. Ser. 39:1–90.

Zhang, J.J. 1996. A molecular biosystematic study on North American Solidago and related genera (Asteraceae: Astereae) based on chloroplast DNA RFLP analysis. Ph.D. diss., Univ. of Waterloo, Waterloo, Ontario, Canada.

 

24. CHRYSOPSIS (Nutt.) Ell., Sketch Bot. S.C. and Ga. 2:333. 1824 (nom. conserv.).

 

 Inula sect. Chrysopsis Nutt., Gen. N. Amer. Pl. 2:150. 1818.

Heterotheca sect. Chrysopsis (Nutt.) Harms, Wrightia 4:12. 1968.

Diplopappus Cass., Bull. Soc. Philom. (Paris) 1817:137. 1817 [see Nesom 1993].

Diplogon Raf., Amer. Monthly Mag. 2:268. 1818.

Bradburia Torr. & A. Gray, Fl. N. Amer. 2:250. 1842.

Chrysopsis subg. Phyllopappus Nutt., Trans. Amer. Philos. Soc. 2, 7:316. 1841.

 

Perennial or annual herbs, woolly or sericeous to arachnoid with silky hairs, the perennials usually producing short to long rhizomes, the stems erect, ascending, or decumbent, 1–9 dm tall. Leaves alternate, sessile, basal and cauline, the basal and lower cauline spatulate to oblanceolate, 3–8 cm long. Heads in a corymboid inflorescence, usually on short branches originating near the top of the main stem; involucres hemispheric, campanulate, or turbinate, 6–12 mm high; phyllaries linear, imbricated in (2–)3–5 series, keeled, without herbaceous tips; receptacle flat, without bracts. Ray florets 13–34, pistillate, fertile, yellow. Disc florets perfect, fertile (ovaries sterile in one species), the lobes deltate, erect; style branches with narrowly lanceolate collecting appendages. Cypselae obovate to linear-oblong in outline, 1.5–3 mm long, nearly terete to slightly flattened, strigose, 5–10-ribbed, these sometimes accompanied by orange-resinous oil ducts; pappus in 2 series, the outer of very short bristles, the inner of long capillary bristles. Base chromosome number, x=5, reduced to x=4 in three species, to x=3 in one; one species is an allopolyploid with chromosome number of 2n=18 (Semple 1977). (Greek, chrysos, gold, -opsis, appearance. “In allusion to the prevailing yellow color of the flowers.” – Nuttall 1818)

      Type species: Chrysopsis mariana (L.) Ell.

      A genus of about 11 species essentially restricted to the Atlantic and Gulf Coastal plains of the southeastern United States and westward to east Texas. On a broader scale, “floristicians for much of the last 75 years have followed either the Gray scheme (a small Heterotheca [Heterotheca s. str. = sect. Heterotheca] and a large Chrysopsis including [Heterotheca sects. Phyllotheca and Ammodia and] Pityopsis) or the Shinners scheme (a single genus Heterotheca including Chrysopsis and Pityopsis)” (Semple 1996, p. 3; see also comments by Cronquist 1977). Small (1933), in contrast, recognized each of these three genera (Heterotheca, Chrysopsis, and Pityopsis) as distinct, and this approach has more recently been supported in detail, particularly based on differences in vestiture, cypsela morphology, and base chromosome number (Semple 1977; Semple et al. 1980; Nesom 1991b).

      A ditypic Chrysopsis sect. Bradburia (Torr. & A. Gray) Nesom was created by uniting the monotypic genus Bradburia (B. hirtella Torr. & A. Gray, as Chrysopsis texana Nesom) with its evolutionary sister species, C. pilosa Nutt. (Nesom 1991a, comments in 1997). Semple (1996) proposed the “alternative solution” (without other justification) of enlarging Bradburia as a genus by including C. pilosa. Bradburia clearly is the sister group to the remainder of Chrysopsis; maintaining Bradburia at generic rank suggests that similar adjustments should be made in the related genus Heterotheca (each of the three sections should be treated as a separate genus), assuming that sect. Bradburia is correctly assessed as the sister group to Chrysopsis s. str.

 

references

 

Cronquist, A. 1977. Notes on the Asteraceae of the southeastern United States. Brittonia 29:217–225.

Harms, V.L. 1965. Cytogenetic evidence supporting the merger of Heterotheca and Chrysopsis (Compositae). Brittonia 17:11–16.

Nesom, G.L. 1991a. Union of Bradburia with Chrysopsis (Asteraceae: Astereae), with a phylogenetic hypothesis for Chrysopsis. Phytologia 71:109–121.

Nesom, G.L. 1991b. A phylogenetic hypothesis for the goldenasters (Asteraceae: Astereae). Phytologia 71:136–151.

Nesom, G.L. 1993. Comments on the definition of the genus Diplopappus Cass. (Asteraceae: Astereae). Phytologia 75:113–116.

Nesom, G.L. 1997. Review: Revision of Heterotheca sect. Phyllotheca (Nutt.) Harms (Compositae: Astereae) by John C. Semple. Phytologia 83:7–21.

Semple, J.C. 1977. Cytotaxonomy of Chrysopsis and Heterotheca (Compositae–Astereae): a new interpretation of phylogeny. Canad. J. Bot. 55:2503–2513.

Semple, J.C. 1981. A revision of the genus Chrysopsis (Nutt.) Ell. nom. cons. Rhodora 83:323–384.

Semple, J.C. 1984. Observations on the cytology, morphology, and ecology of Bradburia hirtella (Compositae–Astereae). Syst. Bot. 9:95–101.

Semple, J.C. 1996. A revision of Heterotheca sect. Phyllotheca (Nutt.) Harms (Compositae: Astereae). Univ. of Waterloo Biol. Ser. 37:i–iv, 1–164.

Semple, J.C. and C.C. Chinnappa. 1980. Karyotype evolution and chromosome numbers in Chrysopsis (Nutt.) Ell. sensu Semple (Compositae–Astereae). Canad. J. Bot. 58:164–171.

Semple, J.C. and C.C. Chinnappa. 1983. Observations on the cytology, morphology, and ecology of Bradburia hirtella (Compositae–Astereae). Syst. Bot. 9:95–101.

Semple, J.C. and C.C. Chinnappa. 1986. The cytogeography of Chrysopsis mariana (Compositae: Astereae): Survey over the range of the species. Rhodora 88:261–266.

Semple, J.C., V. Blok, and P. Heiman. 1980. Morphological, anatomical, habit, and habitat differences among the goldenaster genera Chrysopsis, Heterotheca and Pityopsis (Compositae – Astereae). Canad. J. Bot. 58:164–171.

Small, J.K. 1933. Manual of the Southeastern Flora. Univ. of North Carolina Press, Chapel Hill.

 

25. CHRYSOTHAMNUS Nutt., Trans. Amer. Philos. Soc. 2, 7:323. 1841 [nom. conserv. prop.].

 

Small, rounded shrubs or suffrutescent herbs with much-branched, usually strictly erect stems, often resinous, 1–20 dm tall. Leaves alternate, linear to spatulate-oblanceolate, 1–9 cm long, distinctly 3-nerved in some, glabrous to variously pubescent, punctate-resinous, often varnished. Heads in compact, corymbose clusters; involucres turbinate-cylindric to cylindric, 4–10(–17) mm high; phyllaries triangular-lanceolate to ovate-lanceolate, with a single, golden-resinous midvein, usually with a green apical patch, strongly graduated in 4–5 series in distinct vertical ranks; receptacles without chaff. Ray florets absent or present but few in one species. Disc florets mostly 4–5, perfect, fertile, yellow, the corollas tubular, gradually ampliated or the tube sometimes abruptly expanded into the limb; style branches with linear collecting appendages. Cypselae narrowly ellipsoid, 2–7 mm long, 5–10(–15) nerved, subterete, glabrous to densely sericeous, sometimes glandular near the apex; pappus of numerous, barbellate bristles in 2–3 series, the bristles of unequal length, sometimes dilated at the apex. Base chromosome number, x=9. (Greek, chrysos, gold, thamnos, bush or shrub, for its “affinity to Chrysocoma, and brilliant golden yellow flowers,” according to Nuttall.)

      Lectotype species: Chrysothamnus pumilus Nutt. (= C. viscidiflorus (Hook.) Nutt.) [typ. conserv. prop.; Reveal and Anderson 1995].

      A genus of about 13 species, all primarily endemic to the western USA and southwestern Canada, with only one species reaching into north-central Mexico. Plants of Chrysothamnus are recognized by their shrubby habit, terminal, corymboid clusters of cylindric, eradiate (usually) heads with strongly graduate phyllaries in more or less vertical ranks. Gary Baird (ms.) suggests that a broadened concept of the genus, with inclusion of several satellites, including Petradoria, Hesperodoria, and perhaps Vanclevea, provides a more evolutionary coherent group. Two of the most common and widespread species traditionally associated with Chrysothamnus have recently been transferred to Ericameria as E. nauseosa (Pallas ex Pursh) Nesom & Baird and E. parryi (A. Gray) Nesom & Baird (Nesom & Baird 1993). These two species fit into a previously delimited natural group within Ericameria and are known to hybridize with other species of that genus. See Anderson (1995), however, and Nesom and Baird (1995) for dissent and comments on the definitions of Chrysothamnus and Ericameria. Also see other comments regarding Petradoria and Hesperodoria.

 

references

 

Anderson, L.C. 1964. Taxonomic notes on the Chrysothamnus viscidiflorus complex (Astereae, Compositae). Madrono 17:222–227.

Anderson, L.C. 1966. Cytotaxonomic studies in Chrysothamnus (Astereae, Compositae). Amer. J. Bot. 53:204–212.

Anderson, L.C. 1970a. Floral anatomy of Chrysothamnus (Astereae, Compositae). Sida 3:466–503.

Anderson, L.C. 1970b. Embryology of Chrysothamnus (Astereae, Compositae). Madrono 20:337–342.

Anderson, L.C. 1983. Chrysothamnus eremobius (Asteraceae): a new species from Nevada. Brittonia 35:23–27.

Anderson, L.C. 1986. An overview of the genus Chrysothamnus (Asteraceae). Pp. 29–45 in McArthur, E.D. and L. Bruce (compilers), Proceedings – symposium on the biology of Artemisia and Chrysothamnus. General Technical Report INT-200, U.S.D.A., Forest Service, Ogden, Utah.

Anderson, L.C. 1995. The Chrysothamnus – Ericameria connection. Great Basin Naturalist 55:84–88.

Baird, G.I. Manuscript. A redefinition of Chrysothamnus (Asteraceae: Astereae).

Hall, H.M. and F.E. Clements. 1923. The phylogenetic method in taxonomy. The North American species of Artemisia, Chrysothamnus, and Atriplex. Publ. Carnegie Inst. Washington 326.

Nesom, G.L. and G.I. Baird. 1993. Completion of Ericameria, (Asteraceae: Astereae), diminution of Chrysothamnus. Phytologia 75:74–93.

Nesom, G.L. and G.I. Baird. 1995. Comments on "the Chrysothamnus – Ericameria connection." Phytologia 78:61–65.

Nuttall, T. 1841. Descriptions of new species and genera of plants in the natural order of the Compositae, collected ... during the years 1834 and 1835. Trans. Amer. Philos. Soc. 2, 7:283–453.

Reveal, J.L. and L.C. Anderson. 1995. Proposal to conserve Chrysothamnus Nutt. (Compositae) with a conserved type. Taxon 44:443–444.

Stevens, J.F., E. Wollenweber, M. Ivancic, V.L. Hsu, S. Sundberg, and M.L. Deinzer. 1999. Leaf surface flavonoids of Chrysothamnus. Phytochem. 51:771-780.

 

26. COLUMBIADORIA Nesom, Phytologia 71:249. 1991.

 

Perennial subshrubs with woody, branched bases, arising from a stout taproot, the stems 3–6 dm tall, strict, mostly unbranched below the inflorescence. Leaves eglandular or obscurely punctate-glandular, not resinous, sparsely scabrous-hispidulous, oblanceolate, entire, net-veined, sessile and epetiolate, the largest 2–5 cm long, gradually reduced in size upwards, the basal usually not persistent. Heads 5–15 or more in a racemoid or loosely spicate to loosely corymboid inflorescence; involucres cylindric-turbinate, 8–11 mm high, phyllaries lanceolate, convex, with a green apex, the lower 2/3 white-indurate, not keeled or slightly so on the distal half, in 5–6 graduated series. Rays florets commonly ca. 5 or 8, pistillate, fertile, yellow, 6–10 mm long, the lamina 6–7 mm long, 2 mm wide, weakly if at all coiling. Disc florets perfect, fertile, the corollas yellow, 6–7 mm long, the lobes deltate, erect; style branches with linear-lanceolate appendages 5–6 times longer than the stigmatic lines, papillate toward the apex. Cypselae narrowly oblong, 4–5 mm long, slightly compressed, 8-nerved, moderately strigose with stiff hairs; pappus of a single series of barbellate bristles with attenuate apices. Base chromosome number, unknown, predicted x=9. (Columbia, from the Columbia River, and “doria,” an early name for the goldenrod.)

      Type species: Columbiadoria hallii (A. Gray) Nesom.

      A monotypic genus endemic to the vicinity of the eastern Columbia River Gorge in northern Oregon and southern Washington; “also at scattered stations [south] in the Cascades to the Calapooia Mts.” (Cronquist 1955). Plants of Columbiadoria are recognized by their subshrubby habit with erect, little-branched stems, oblanceolate, entire, net-veined leaves, and large heads in a spicate or racemoid to loosely corymboid inflorescence, the rays few but long and conspicuous. Cronquist (1955, p. 216) noted that “the specimens occurring [south] from the Columbia gorge region are not precisely like the others, and may prove to be varietally distinct.” Columbiadoria was hypothesized (Nesom 1991) to be a member of the Petradoria group, although it lacks the characteristic linear-lanceolate, parallel-veined leaves of those species and apparently is primitive among its relatives.

 

references

 

Cronquist, A. 1955. Part 5: Compositae. Vascular Plants of the Pacific Northwest. Univ. of Washington Press, Seattle.

Hall, H.M. 1928. The genus Haplopappus – A phylogenetic study in the Compositae. Section 12. Hesperodoria. Carnegie Inst. Washington Publ. No. 389:35, 218–222.

Nesom, G.L. 1991. Redefinition of Hesperodoria (Asteraceae: Astereae) and the segregation of Columbiadoria, a new monotypic genus from the western United States. Phytologia 71:244–251.

 

27. CONYZA Less., Syn. Gen. 203. 1832 [nom. conserv.; Conyza L. rejec.].

 

 Erigeron sect. Caenotus Nutt., Gen. Pl. 2:148. 1818.

Erigeron sect. Conyza (L.) Baillon, Hist. Pl. 8:143. 1882.  [inapplicable name, because Conyza L. has been rejected in favor of Conyza Less.]

Conyza sect. Caenotus (Nutt.) Cronq. ex Cuatr., Webbia 24:211. 1969.

Conyzella Fabric., Enum. (ed. 1) 86. 1759.

Leptilon Raf., Amer. Monthly Mag. 268. 1818.

 

 

Annual or perennial herbs 1.5–20 dm tall, nearly glabrous to coarsely hispid-pilose. Leaves linear to oblanceolate, 2–15 cm long, entire to toothed or pinnatifid. Heads in a broadly ellipsoid to columnar inflorescence, or sometimes somewhat flat-topped; involucres cylindric to hemispheric, 3–8 mm high; phyllaries in 2–4 subequal to slightly graduate series, sometimes often into a hypanthium-like cup and appearing inserted on it, the outer usually with 3, orange-resinous nerves. Ray florets pistillate, fertile, in numerous series, the corollas eligulate or with a lamina that barely exceeds the phyllaries in length. Disc florets perfect, fertile, 3–35, the corollas tubular-funnelform, 2–4 mm long (–5 mm in C. primulifolia), with the tube ca. 2/3 the total length; style branches with deltate collecting appendages. Cypselae oblong, 0.8–1.8 mm long, flattened, with 2, thin, marginal nerves, glabrous to sparsely strigose, eglandular; pappus a single series of barbellate bristles, sometimes accrescent, uncommonly with a short outer series of setae. Base chromosome number, x=9. (Greek, konis, dust, from the use of powdered plants to repel insects.)

      Type species: Conyza chilensis Spreng. [typ. conserv.].

      A genus of about 60–100 species, primarily from tropical and subtropical America, including a number of species that are cosmopolitan colonizers (Thιbaud & Abbott 1995). Conyza is closely similar to Erigeron and the two have long been considered to be closely related (Cronquist 1943; Zardini 1976; McVaugh 1984; Nesom 1994). Conyza has been distinguished from Erigeron primarily by its much greater number (relatively) of pistilllate florets with slender, highly reduced rays. In addition, in Conyza the phyllaries usually are 3-nerved, the disc florets are less numerous with shorter corollas, and the pappus at maturity sometimes is accrescent. The dense, paniculate inflorescences and cylindric heads (in vivo) of some Conyza species are not characteristic of Erigeron. ITS data (Noyes 2000), however, indicate that New World Conyza is polyphyletic (apparently at least triphyletic) and completely imbedded within Erigeron, as currently conceived.

      The separation of Laennecia from Conyza (Zardini 1981; Nesom 1990a) allowed a better definition of the latter (Nesom 1990b), but many species have been described from South America in the last 40 years and the whole group is in need of study. Old World species identified as Conyza are related to genera outside of the Conyzinae, as suggested by Nesom (1990) and tentatively confirmed by molecular studies (Noyes 2000; Noyes & Rieseberg 1999). The genera Eschenbachia Moench, Dimorphanthes Cass., and Edemias Raf. are typified by Conyza aegyptica (L.) Ait., an African species; Marsea Adanson and Fimbrillaria Cass. are typified by Conyza ivifolia (L.) Less., also an African species. The Linnaean Conyza was lectotypified by C. squarrosa L. an Old World species, by M.L. Green (Prop. Brit. Bot. 181. 1929; also see Jarvis et al. 1993 and Rechinger, Fl. Iran. 145:92. 1980). The genus is now conserved, however, by Lessing’s concept and the conserved generitype, C. chilensis Spreng., a New World species.

 

references

 

Cronquist, A. 1943. The separation of Erigeron from Conyza. Bull. Torrey Bot. Club 70: 629–632.

Cuatrecasas, J. 1969. Conyza. Prima flora Colombiana. 3. Compositae – Astereae. Webbia 24:198–228.

Jarvis, C.E., F.R. Barrie, D.M. Allan, and J.L. Reveal. 1993. A list of Linnaean generic names and their types. Regnum Veg. 127:1–100.

Nesom, G.L. 1990a. Taxonomy of the genus Laennecia (Compositae: Astereae). Phytologia 68:205–228.

Nesom, G.L. 1990b. Further definition of Conyza (Compositae: Astereae). Phytologia 68:229–233.

Nesom, G.L. 1994a. Subtribal classification of the Astereae (Asteraceae). Phytologia 76:193–274.

Noyes, R.D. 2000. Biogeographical and evolutionary insights on Erigeron and allies (Asteraceae) from ITS sequence data. Pl. Syst. Evol. 220:93–114.

Noyes, R.D. and L.H. Rieseberg. 1999. ITS sequence data support a single origin of North American Astereae (Asteraceae) and reflect deep geographic divisions in Aster s.l. Amer. J. Bot. 86:398–412.

Thιbaud, C. and R.J. Abbott. 1995. Characterization of invasive Conyza species (Asteraceae) in Europe: quantitative trait and isozyme analysis. Amer. J. Bot. 82:360–368.

Zardini, E. M. 1976. Contribuciones para una monografia del genero Conyza Less. I. Bol. Soc. Argentina Bot. 17:31–46.

Zardini, E. M. 1981. Contribuciones para una monografia del genero Conyza Less. II. Rehabilitacion del genero Laennecia Cass. Darwiniana 23:160–169.

 

28. CORETHROGYNE DC., Prodr. 5:215. 1836.

 

Herbaceous perennials, 1–8 dm tall, often woody at the base, white-tomentose, commonly glabrescent or glabrate, prominently stipitate-glandular in some species. Leaves alternate, linear to obovate, 1–7 cm long, toothed to entire, petiolate to sessile. Heads solitary or 2–5(–20) in a spicate to loosely corymbiform capitulescence; involucres hemispheric to campanulate or turbinate, 5–13 mm high; phyllaries graduated in 3–8 series, often with a green, apical patch, the tips often spreading to deflexed; receptacle flat to shallowly convex, shallowly alveolate. Ray florets 10-40 in a single series, pistillate but with sterile ovaries, corollas white to blue or pink, straight or coiling slightly at the tips. Disc florets perfect, fertile, yellow; style branches with deltate to ovate collecting appendages densely hispid with stiff, spreading hairs. Cypselae terete or slightly compressed, 3–5 mm long, 5–8-ribbed, moderately to densely strigose-sericeous; pappus of numerous, slightly tawny to rusty-red, barbellate bristles in 1–2 series, without a shorter, outer series. Base chromosome number, x=5. (Greek, korethron, broom, gyne, female, in reference to hairy, “broomlike” collecting appendages of the disc style branches.)

      Type species: Corethrogyne californica DC.

      Corethrogyne is endemic to the Pacific coast of North America, where it occurs from Oregon to northern Baja California. Ferris (1960), who has provided the most complete published treatment to date, recognized seven species and seven varieties; Keck (1959) recognized 3 species and 17 varieties; Saroyan et al. (submitted) propose to reduce the complex to a single species, C. filaginifolia (Hook. & Arn.) Nutt., with two varieties. Although putative taxa of Corethrogyne have been viewed as intergrading and difficult to circumscribe, the genus itself is easily distinguished by perennial duration, loose inflorescence, tomentose and glandular vestiture, strongly graduated, green-tipped phyllaries, sterile ray florets with purple, pink, or white lamina, and spreading-hispid collecting appendages of the disc style branches. Lane (1993a, 1993b) proposed to consolidate Lessingia, Corethrogyne, and the monotypic, central Californian endemic genus Benitoa by including them all within Lessingia (which see); she followed the taxonomic suggestion of Saroyan et al. for the corethrogynoid taxa. Nesom (1994) noted that the narrower concept of three genera, as followed here, appears to be equally or more defensible on phenetic and phylogenetic grounds.

 

references

 

Canby, M.L. 1927. The genus Corethrogyne in southern California. Bull. South. Calif. Acad. 26:8–16.

Ferris, R.S. 1960. Corethrogyne. Pp. 337–342 in L. Abrams and R.S. Ferris (eds.). Illustrated flora of the Pacific States, Vol. 4. Stanford Univ. Press, Stanford, California.

Lane, M.L. 1993a. New combinations in Californian Lessingia (Compositae: Astereae). Novon 3:213–214.

Lane, M.L. 1993b. Lessingia. Pp. 304–306 in J.C. Hickman (ed.). The Jepson manual: Higher plants of California. Univ. of California Press, Berkeley.

Keck, D.D. 1959. Corethrogyne. Pp. 1204–1207 in P.A. Munz. A California flora. Univ. California Press, Berkeley.

Nesom, G.L. 1994a. Subtribal classification of the Astereae (Asteraceae). Phytologia 76:193–274.

Saroyan, J.P., D.R. Parnell, and J.L. Strother. Submitted. Revision of Corethrogyne (Compositae: Astereae). Madrono.

 

29. CROPTILON Raf., Fl. Tellur. 2:47. 1836 [1837].

 

Isopappus Torr. & A. Gray, Fl. N. Amer. 2:239. 1842.

Haplopappus sect. Isopappus (Torr. & A. Gray) Benth. & J.D. Hook., Gen. Pl. 2:254. 1873.

 

Taprooted annual to weak perennial herbs 3–40 cm tall, usually sparsely hispid, densely stipitate-glandular in all except one. Leaves alternate, sessile, rigid, linear to narrowly oblanceolate to lanceolate, 2–8 cm long, with 3, major, parallel veins, with acute apices, often distinctly falcate, entire to serrate, long-ciliate basally, with thin-arachnoid pubescence in tiny abaxial lacunae. Heads solitary or in a loose, widely branched panicle; involucres narrowly turbinate to subcylindric, 4–8 mm high; phyllaries in 3–5 graduate series, lanceolate to linear-lanceolate; receptacles alveolate, not chaffy. Ray florets pistillate, fertile, 5–30, the lamina bright yellow to yellow-orange, coiling at maturity. Disc florets perfect, fertile, yellow, the lobes triangular and erect; style branches with linear-triangular collecting appendages. Cypselae elongate-turbinate, terete to few-angled, 1.8–3.2 mm long, usually dark brown to purplish, with 6–14 light-colored, thin, superficial nerves, with additional resinous nerves in C. rigidifolium (Smith) Smith, strigose to sericeous; pappus a single series of persistent, thick and rigid, equal-length, tawny to reddish-brown capillary bristles. Base chromosome numbers, x=6, 5, 4. (Greek, kropion, scythe, ptilon, wing or feather, perhaps in allusion to a perceived wing-like or feather-like appearance of the curved, pinnately toothed leaves, the allusion to “feather” explicitly made by Rafinesque, “col. feather,” but not explained.)

      Type species: Croptilon divaricatum (Nutt.) Raf.

      A genus of three species from the south-central and southeastern USA and northeastern Mexico. Croptilon hookerianum (Torr. & A. Gray) House has three varieties. It was revised as a section of Haplopappus by Smith (1965, 1966), who later (1981) came to agree with Shinners (1951) that the group should stand as a separate genus. Croptilon is one of the goldenaster genera (subtribe Chrysopsidinae) and is hypothesized to be most closely related to Pityopsis (Nesom 1991), based on the predominance of thin-based arachnoid trichomes, narrow, parallel-veined leaves, sclerenchymatous veins, small heads, and subterete cypselae. It is further distinguished by a taprooted habit, narrow, rigid, and basally ciliate leaves, turbinate, few-rayed heads in a loose inflorescence, and reduced chromosome number(s).

 

references

 

Hall, H.M. 1928. The genus Haplopappus – A phylogenetic study in the Compositae. Section 11. Isopappus. Carnegie Inst. Washington Publ. No. 389:35, 212–218.

Nesom, G.L. 1991. A phylogenetic hypothesis for the goldenasters (Asteraceae: Astereae). Phytologia 71:136–151.

Shinners, L.H. 1951. Notes on Texas Compositae. VIII. Field and Lab. 19:134.

Smith, E.B. 1965. Taxonomy of Haplopappus section Isopappus (Compositae). Rhodora 67:217–238.

Smith, E.B. 1966. Cytogenetics and phylogeny of Haplopappus section Isopappus (Compositae). Canad. J. Genet. & Cytol. 8:14–36.

Smith, E.B. 1981. New combinations in Croptilon (Compositae – Astereae). Sida 9:59–63.

 

30. DICHAETOPHORA A. Gray, Mem. Amer. Acad. Arts 2, 4:73 [Pl. Fendl. 73]. 1849.

 

Boltonia sect. Dichaetophora (A. Gray) Benth. & Hook., Gen. Pl. 2:269. 1873.

 

Annual herbs from a thin taproot, the stems basally erect or decumbent, 4–24 cm tall, sparsely strigose. Leaves alternate, oblanceolate, 1–4 cm long, entire. Heads terminal, solitary, on peduncles 2–9 cm long; involucres hemispheric, 3–4.5 mm high; phyllaries lanceolate, in 2 subequal series, prominently long-ciliate; receptacles convex to conical, without chaff. Ray florets pistillate, fertile, 15–25, the lamina white above, lavender-tinged beneath and often drying with a bluish-purple midstripe. Disc florets perfect, fertile, the corollas 1.5–2 mm long, abruptly contracted at the base to form a very short tube. Cypselae obovate to widely elliptic, 2–2.5 mm long, strongly laterally compressed, with a thickened, narrowly elliptic-lanceolate to elliptic central area surrounded by lighter colored wing-like margins, the central area with a dense covering of long, whitish, duplex, glochidiate hairs, the wings glabrous, margins pilose-fringed with similar glochidiate hairs; pappus of 2 thin, ascending, barbellate awns 0.6–1.2 mm long, usually with several additional minute ones ca. 0.2 mm long, forming an elliptic ring with the long awns on either end. Base chromosome number, x=3. (Greek, di- two, chaite, long hair, -phor, bear or carry, in reference to the two awn-like pappus elements.)

      Type species: Dichaetophora campestris A. Gray.

      A monotypic genus of south-central Texas southward into adjacent Mexico, characterized by an annual habit, oblanceolate leaves, small, white-rayed heads with broad, scarious-margined phyllaries. The cypselae are primarily 2-awned and have long, glochidiate hairs covering the faces and the winged margins. Dichaetophora is similar and apparently closely related to Astranthium and it has the same chromosome number (2n=6) as northern species of Astranthium. Johnston (1970) commented that A. integrifolium and Dichaetophora are separated by a "few technical differences in achene and pappus ..." and "almost certainly ... should be congeneric." This may prove to be the case, but inclusion of the winged and awned cypselae of Dichaetophora would alter the morphological integrity of Astranthium, and more definitive evidence is needed.

 

reference

 

Gray, A. 1849. Plantae Fendlerianae Novi–Mexicanae: an account of a collection of plants made chiefly in the vicinity of Santa Fe, New Mexico, by Augustus Fendler. Mem. Amer. Acad. Arts 2, 4:1–116.

Johnston, M.C. 1970. Asteraceae. In D.S. Correll and M.C. Johnston. Manual of the vascular plants of Texas. Texas Research Foundation, Renner.

Shinners, L.H. 1946. The genus Dichaetophora A. Gray and its relationships. Wrightia 1:90–94.

 

31. DOELLINGERIA Nees, Gen. Sp. Aster. 177. 1832 [1833].

 

Aster subg. Doellingeria (Nees) A. Gray, Synopt. Fl. N. Amer. 1(2):196. 1884.

Aster sect. Doellingeria (Nees) Kitam., J. Jap. Bot. 12:721. 1936.

Aster sect. Teretiachenium Kitamura, Mem. Coll. Sci. Kyoto Univ., ser. B. 8:357. 1937.

Aster sect. Triplopappus (Torr. & A. Gray) A.G. Jones, Brittonia 32:237. 1980.

Kalimeris sect. Cordifolium Kitamura, Mem. Coll. Sci. Kyoto Univ., ser. B. 8:312. 1937.

 

Erect, fibrous-rooted, perennial herbs, 4–20 dm tall, glabrous to sparsely pubescent, eglandular. Leaves all cauline, 4–15 cm long, the lowermost reduced to bracts. Heads in a loose to compact corymboid inflorescence; involucres cylindric-turbinate, 3–7 mm high; phyllaries in 2–4 imbricate series, oblong to oblong-lanceolate, apically rounded to acute with a raised midvein and often several lateral veins, without a herbaceous apical patch; receptacle without chaff. Ray florets pistillate, fertile, 2–11(–16), white, not coiling. Disc florets perfect, fertile, the corollas abruptly ampliate, with lanceolate, reflexing-coiling lobes. Cypselae broadly columnar, plump to somewhat compressed, 3–4 mm long at maturity and equalling the height of the involucre, glabrous to sparsely strigose, eglandular, 5–9-veined, each vein often with a raised, orangish, oil duct; pappus of barbellate, bristles in 2–3 series, the outer series 1 mm or less high, the longer bristles with expanded tips. Base chromosome number, x=9. (For German botanist Ignatz Doellinger, 1770–1841.)

      Type species: Doellingeria umbellata (Mill.) Nees.

      Doellingeria has recently been consolidated as 11 species placed in two sections (Nesom 1993), primarily based on differences in leaf morphology: sect. Doellingeria has lanceolate, epetiolate, and mostly entire leaves, while sect. Cordifolium (Kitamura) Nesom has cordate, petiolate, and serrate leaves. Three of the six species of sect. Cordifolium have reduced pappus. All three eastern North American species are sect. Doellingeria; two of the eight east Asian species are sect. Doellingeria, the six others sect. Cordifolium. These 11 species have often been treated within a broadly defined Aster, but Doellingeria is an early-described genus and recent arguments have been presented for its resegregation (Nesom 1994; Semple et al. 1996). It is distinctive in the corymboid inflorescence, multi-veined phyllaries without an apical patch, few, white rays, plump, shouldered cypselae with 5–9 resinous nerves, multiseriate pappus, and base chromosome number of x=9. Aster reticulatus Pursh has been included within Doellingeria (e.g., Semple et al. 1991) and cpDNA evidence appears to indicate that it is part of that group (Xiang & Semple 1996). Morphological features, in contrast, place A. reticulatus in the genus Oclemena (which see).

      A study of restriction site variation in cpDNA (Ito et al. 1994) indicates that the Asian species Doellingeria sohayakiensis (Koidzumi) Nesom (sect. Doellingeria) and D. japonica (Miq.) Nesom and D. scabra (Thunb.) Nees (sect. Cordifolium) form a monophyletic group, while D. komonoensis (Makino) Nesom and D. dimorphophylla (Franch. & Sav.) Nesom (sect. Cordifolium) are closely related to the others but not strictly monophyletic.

 

references

 

Ito, M., A. Soejima, and T. Nishino. 1994. Phylogeny and speciation of Asian Aster. Korean J. Pl. Taxon. 24:133–143.

Nesom, G.L. 1993. Taxonomy of Doellingeria (Asteraceae: Astereae). Phytologia 75:452–462.

Nesom, G.L. 1994. Review of the taxonomy of Aster sensu lato (Asteraceae: Astereae), emphasizing the New World species. Phytologia 77:141–297.

Semple, J.C., J.G. Chmielewski, and C. Leeder. 1991. A multivariate morphometric study and revision of Aster subg. Doellingeria sect. Triplopappus (Compositae: Astereae): The Aster umbellatus complex. Canad. J. Bot. 69:256–276.

Semple, J.C., S.B. Heard, and C.S. Xiang. 1996. The Asters of Ontario (Compositae: Astereae): Diplactis Raf., Oclemena E.L. Greene, Doellingeria Nees and Aster L. (including Canadanthus Nesom, Symphyotrichum Nees, and Virgulus Raf.). Rev. ed. Univ. of Waterloo Biol. Ser. 38:i–viii, 1–94.

Xiang, C. and J.C. Semple. 1996. Molecular systematic study of Aster s. lat. and related genera (Asteraceae: Astereae) based on chloroplast DNA restriction site analyses and mainly North American taxa. In D.J.N. Hind and H.J. Beentje (eds.). Compositae: Systematics. Vol. 1, pp. 393–423. Proc. Interntl. Compositae Conf., Kew, 1994.

 

32. EASTWOODIA Brandegee, Zoe 4:397. 1894.

 

Rounded shrubs 3–10 dm tall, glabrous, with white and shredding bark on the older stems, usually glutinous. Leaves alternate, punctate and slightly resinous, 1-nerved, linear to linear-oblanceolate, 1.5–4 cm long, entire and sparsely short-ciliate, yellow-green, sometimes in axillary clusters, relatively evenly arranged and little reduced in size to immediately beneath the heads. Heads solitary or in open, corymboid panicles; involucres hemispheric to campanulate, impressed at the base, 4–6 mm high; phyllaries in 3–5 graduate series, thick and stiffly erect, resinous, oblanceolate, green on the distal half, indurate below, with narrow, scarious margins; receptacles with oblanceolate, quickly deciduous chaffy scales. Ray florets absent. Disc florets 30–40, yellow, cylindric to funnel-shaped, the lobes narrowly lanceolate and spreading to reflexing; style branches with triangular-lanceolate collecting appendages. Cypselae narrowly obconic, 1.7–2 mm long, 3–4-angled, strigose-sericeous especially on the angles; pappus of 5–8, flattened, linear-lanceolate, slightly scabrous-margined scales nearly equal the corolla height. Base chromosome number, x=9. (For western American botanist Alice Eastwood, 1859–1953.)

      Type species: Eastwoodia elegans Brandegee.

      A monotypic genus endemic to California along low ranges near the coast from the San Francisco region south to Kern County, recognized by its white-barked, shrubby habit, narrow, punctate-resinous leaves, solitary, discoid heads on leafy stems, chaffy receptacles, and pappus of long scales. Following Lane (1988), Eastwoodia was placed as a member of the “Acamptopappus group” with Acamptopappus and Amphipappus in recent classifications (Nesom 1993, 1994). As noted by Lane, however, these three genera are not particularly coherent in morphology, and recent cpDNA evidence suggests that Eastwoodia may be phyletically distant from the other two (Lane et al. 1996).

 

references

 

Brandegee, T.S. 1894. Two undescribed plants from the Coast Range. Zoe 4:397, 380, pl. 30.

Lane, M.L. 1988. Generic relationships and taxonomy of Acamptopappus (Compositae: Astereae). Madrono 35:247–265.

Lane, M.A., D.R. Morgan, Y. Suh, B.B. Simpson, and R.K. Jansen. 1996. Relationships of North American genera of Astereae, based on chloroplast DNA restriction site data. In D.J.N. Hind and H.J. Beentje (eds.). Compositae: Systematics. Vol. 1, pp. 49–77. Proc. Interntl. Compositae Conf., Kew, 1994.

Nesom, G.L. 1993. Taxonomic infrastructure of Solidago and Oligoneuron (Asteraceae: Astereae) and comments on their phylogenetic position. Phytologia 75:1–44.

Nesom, G.L. 1994. Subtribal classification of the Astereae (Asteraceae). Phytologia 76:193–274.

 

33. EGLETES Cass., Bull. Soc. Philom. (Paris) 1817:153. 1817.

 

Xerobius Cass., Dict. Sci. Nat. 59:128. 1829.

Eyselia Reich., Icon. Bot. Exot. no. 242, pl. 242. 1830.

Platystephium Gardner, London J. Bot. 7:80. 1848.

 

Taprooted, annual herbs with erect to trailing, much-branched stems, 1–6 dm tall, glandular-resinous, sometimes arachnoid in early growth. Leaves alternate, obovate to spatulate but variable in outline, 2–7(–12) cm long, pinnatifid or bipinnatifid to lobed or toothed, petiolate or epetiolate, clasping to subclasping. Heads usually solitary and axillary (but apparently opposite the leaves) or more compact in a few-headed, loosely corymboid inflorescence, usually on naked peduncles; involucres shallowly hemispheric or cupulate, 3–6 mm high; phyllaries in 2–3 equal to subequal series, lanceolate, thin-herbaceous; receptacle conical, without chaff. Rays pistillate, fertile, in 1–4 series, the lamina white, filiform and very short (not exceeding the involucre) or more prominent. Disc florets perfect, fertile, the corollas yellow, tubular-funnelform, with slight differentiation of tube and limb, 3–5 lobed; style branches with triangular collecting appendages. Cypselae oblong to narrowly obovate, slightly compressed, 2-ribbed, 1–1.5 mm long, glabrous or commonly glandular; pappus absent, the summit of the cypsela extended into a whitish, cartilaginous crown or shallow cup, this structure broad and flaring in some species. Base chromosome number, x=9. (Greek, aiylitis, fide Wittstein 1852, apparently referring to an aspect of “splendor” or “glitter,” perhaps of the heads, as translated by Divry 1991.)

      Type species: Egletes domingensis Cass. (= Egletes prostrata (Swartz) Kuntze).

      A genus of the New World tropics, with two of the species reaching Central America, Mexico, and the United States (south-coastal Texas). Shinners (1949a, 1949b) recognized nine species; Aristeguieta (1964) reduced the number by one and noted the ambiguous status of another. Except for Centipeda (see above), which is adventive, Egletes apparently is the only representative of the subtribe Grangeinae in North America. Plants of Egletes are characterized by their low, herbaceous habit, glandular-resinous vestiture, narrow, multiseriate, but often inconspicuous rays, conical receptacles, compressed, glandular cypselae with a coronal apex.

 

references

 

Aristeguieta, L. 1964. Egletes. Flora de Venezuela 10(1):250–255.

Divry, D.C. (ed.). 1991. Divry’s modern English–Greek Desk dictionary. Divry Inc., Publishers, New York.

Pruski, J.F. 1995. Asteraceae. Flora of the Venezuelan Guayana 3:177–393 [Egletes, pp. 265–266].

Shinners, L.H. 1949a. Revision of the genus Egletes Cassini north of South America. Lloydia 12:239–247.

Shinners, L.H. 1949b. Two additions to the genus Egletes Cassini from northern South America. Lloydia 12:248–250.

Wittstein, G.C. 1852. Etymologisch–botanisches Handwφrterbuch. Verlag von Carl Junge, Ansbach.

 

34. ERICAMERIA Nutt., Trans. Amer. Philos. Soc. 2, 7:318. 1841.

 

Haplopappus sect. Ericameria (Nutt.) A. Gray, Pl. Wright. 2:80. 1853.

Haplopappus sect. Asiris H.M. Hall, Carnegie Inst. Washington, Yearb. 25:342. 1926.

Haplopappus sect. Macronema (Nutt.) A. Gray, Proc. Amer. Acad. Arts 6:542. 1865.

Haplopappus sect Stenotopsis (Rydb.) Urbatsch & Wussow, Brittonia 31:273. 1979.

Macronema Nutt., Trans. Amer. Philos. Soc. 2, 7:322. 1841.

Stenotopsis Rydb., Bull. Torrey Bot. Club 23:617. 1900.

Tumionella Greene, Leafl. Bot. Obs. Crit. 1:173. 1906.

 

Perennial, evergreen shrubs 1–30(–50) dm tall, nearly arborescent in a few, often intricately branched, commonly glutinous, densely tomentose in some. Leaves dark green, firm, linear to spatulate, 0.2–6 cm long, short-petiolate or sessile, usually punctate-glandular and resinous, often crowded with short internodes. Heads solitary, in leafy racemes or thyrsoid panicles, or commonly in densely crowded in corymboid inflorescences; involucres turbinate to subcampanulate, 4–13 mm high, the phyllaries mostly in 3–5 series subequal to strongly graduated in length, with an orange-glandular midrib from base to tip. Ray florets 0–10, yellow, pistillate and fertile, the lamina coiling with maturity. Disc florets perfect, fertile, exceeding the involucre, orange-nerved, the lobes triangular, equal to slightly unequal in length, erect to spreading-recurved; style branches with lanceolate to linear-lanceolate collecting appendages. Cypselae flat, rarely terete, narrowly oblong, 2–10 mm long, 6–12 ribbed, usually moderately to densely strigose to sericeous; pappus of barbellate bristles in 2–3 persistent series (sect. Macronema and part of sect. Ericameria) or 1(–2) series of basally caducous bristles (sects. Stenotopsis and Asiris and part of sect. Ericameria), longer than the disc corollas. Base chromosome number, x=9. (“So named from a resemblance to the genus Erica in the minute sempervirent leaves.” – Nuttall 1841)

      Type species: Ericameria microphylla Nutt., nom. illeg. (= Ericameria ericoides (Less.) Jepson).

      A genus of 31 species of shrubs or subshrubs in the western United States and northwestern and north-central Mexico. The genus Xylothamia was created (Nesom et al. 1990) to include seven species previously regarded as Ericameria but which may be more closely related to Solidago and Euthamia. Ericameria is characterized by phyllaries with a orange-resinous midline, lacking a glandular apical patch, and disc corollas with relatively shallow, regular lobes. Many of the species have punctate-resinous leaves. Differences in pappus morphology within sect. Ericameria suggest that it may be polyphyletic. The genus was broadened by Nesom (1990) to encompass species formerly included in Haplopappus sects. Macronema and Asiris, some of which were originally described as Ericameria. As currently delimited, Ericameria includes four sections: sect. Ericameria, sect. Asiris (Hall) Nesom, sect. Macronema (Nutt.) Nesom, and sect. Stenotopsis (Rydb.) Urb. & Wussow. Nesom and Baird (1993, 1995) further included four species traditionally treated within the genus Chrysothamnus, including the widespread and conspicuous Ericameria (Chrysothamnus) nauseosa (Pallas ex Pursh) Nesom & Baird and E. (Chrysothamnus) parryi (A. Gray) Nesom & Baird, all accomodated within pre-existing sections of Ericameria. Anderson (1995) responded by transferring all species of Chrysothamnus to Ericameria. Similarly, Semple et al. (1989, p. 309) noted that “species in [Ericameria and Macronema], and those in Chrysothamnus, form a natural alliance that cannot be separated into well-defined groups worthy of generic recognition, unless arbitrary character limits are adopted. We think that all taxa probably should be included under a single generic name, Chrysothamnus.” In the concept of Nesom and Baird, hybrids formerly seen as intergeneric crosses between Ericameria and Chrysothamnus (Anderson & Reveal 1966; Anderson 1986, 1993) can be interpreted as interspecific crosses within Ericameria.

 

references

 

Anderson, L.C. 1986. An overview of the genus Chrysothamnus (Asteraceae). Pp. 29–45 in E.D. McArthur and L. Bruce (compilers). Proceedings – symposium on the biology of Artemisia and Chrysothamnus. General Technical Report INT-200, U.S.D.A., Forest Service, Ogden, Utah.

Anderson, L.C. 1993. Chrysothamnus. Pp. 229–232 in J.C. Hickman (ed.). The Jepson manual: Higher plants of California. Univ. of California Press, Berkeley.

Anderson, L.C. 1995. The Chrysothamnus – Ericameria connection. Great Basin Naturalist 55:84–88.

Anderson, L.C. and J.L. Reveal. 1966. Chrysothamnus bolanderi, an intergeneric hybrid. Madrono 18:225–256.

Greene, E.L. 1906. New Asteraceous genera. Leafl. Bot. Observ. Crit. 1:173–174.

Hall, H.M. 1907. Compositae of southern California. Univ. of California Publ. Bot. 3:1–302 [Ericameria, pp. 51–56].

Hall, H.M. 1928. The genus Haplopappus – A phylogenetic study in the Compositae. Section 6. Stenotopsis. Carnegie Inst. Washington Publ. No. 389:34, 156–161.

Hall, H.M. 1928. The genus Haplopappus – A phylogenetic study in the Compositae. Section 9. Macronema. Carnegie Inst. Washington Publ. No. 389:35, 187–208.

Hall, H.M. 1928. The genus Haplopappus – A phylogenetic study in the Compositae. Section 15. Ericameria. Carnegie Inst. Washington Publ. No. 389:36, 258–288.

Hall, H.M. 1928. The genus Haplopappus – A phylogenetic study in the Compositae. Section 16. Asiris. Carnegie Inst. Washington Publ. No. 389:36, 288–300.

Nesom, G.L. 1990. Taxonomic summary of Ericameria (Asteraceae: Astereae), with the inclusion of Haplopappus sects. Macronema and Asiris. Phytologia 68:144–155.

Nesom, G.L., D.R. Morgan, Y. Suh, and B.B. Simpson. 1990. Xylothamia (Asteraceae: Astereae), a new genus related to Euthamia. Sida 14:101–116.

Nesom, G.L. and G.I. Baird. 1993. Completion of Ericameria (Asteraceae: Astereae), diminution of Chrysothamnus. Phytologia 75:74–93.

Nesom, G.L. and G.I. Baird. 1995. Comments on "the Chrysothamnus – Ericameria connection." Phytologia 78:61–65.

Nuttall, T. 1841. Descriptions of new species and genera of plants in the natural order of the Compositae, collected ... during the years 1834 and 1835. Trans. Amer. Philos. Soc. 2, 7:283–453.

Semple, J.C., J.G. Chmielewski, and M.A. Lane. 1989. Chromosome number determinations in fam. Compositae, tribe Astereae. III. Additional counts and comments on generic limits and ancestral base numbers. Rhodora 91:296–314.

Urbatsch, L.E. 1976. Systematics of the Ericameria cuneata complex (Compositae, Astereae). Madrono 23:338–345.

Urbatsch, L.E. 1978. The Chihuahuan Desert species of Ericameria (Compositae: Astereae). Sida 7:298–303.

Urbatsch, L.E. and J.R. Wussow. 1979. The taxonomic affinities of Haplopappus linearifolius (Asteraceae – Astereae). Brittonia 31:265–275.

 

35. ERIGERON L., Sp. Pl. 683. 1753 [nom. conserv. prop.].

 

Trimorpha Cass., Bull. Sci. Soc. Philom. Paris 1817:137. 1817.

Stenactis Cass., Dict. Sci. Nat. 37:485. 1825.

Phalacroloma Cass., Dict. Sci. Nat. 39:404. 1826.

Polyactis Less., Syn. Gen. Comp. 188. 1832.

Terranea Colla, Mem. Reale Accad. Sci. Torin. 38:11. 1835.

Musteron Raf., Fl. Tellur. 2:50. 1836.

Fragmosa Raf., Fl. Tellur. 2:50. 1836.

Diplemium Raf., Fl. Tellur. 2:50. 1836.

Heterochaeta DC., Prodr. 5:282. 1836.

Polyactidium DC., Prodr. 5:281. 1836.

Woodvillea DC., Prodr. 5:318. 1836.

Achaetogeron A. Gray, Mem. Amer. Acad. Arts 2, 4 [Pl. Fendl.]: 72. 1849.

Astradelphus Remy, Ann. Sci. Nat. Bot. ser. 3, 12:185. 1849.

Wyomingia A. Nelson, Bull. Torrey Bot. Club 26:249. 1899.

Asterigeron Rydb., Fl. Rocky Mts. 891. 1918.

Darwiniothamnus Harling, Acta Horti Berg. 20:108. 1962.

 

Annual, biennial, or perennials, herbaceous, less commonly suffrutescent, rarely shrubs or small trees, 0.2–17 dm tall, from a simple or branched caudex, and from a taproot, fibrous roots, or rhizomes. Stems, leaves, and phyllaries glabrous to variously pubescent, commonly with minute (granular) to prominent (stipitate) biseriate, gland-tipped hairs. Leaves linear to lanceolate, oblanceolate, or spatulate, entire to toothed or pinnatifid, 0.5–15 cm long, entire to toothed or deeply lobed, the basal rosette sometimes persistent, cauline leaves alternate, clasping or not. Heads solitary or few to numerous and loosely corymboid or paniculate; buds erect, nodding, or arching-pendant; involucres turbinate to hemispheric, 3–11 mm high; phyllaries with 1 (rarely 3) golden-resinous midvein, in 2–4(–7) equal to strongly graduated series; receptacles flat to sharply conical, foveolate to alveolate, epaleate. Ray florets pistillate, fertile, in 1–4 series, rarely completely absent, the lamina white to blue or pink, less commonly yellow, reflexing, coiling, or remaining straight at maturity, or the pistillate florets eligulate. Disc florets perfect, fertile, the corollas yellow, sharply to barely constricted in the lower 1/6–1/3, sometimes strongly inflated and indurated above the tube. Cypselae oblong to oblong-obovate, (0.5–)0.8–3 mm long, laterally compressed, with 2–4 thin to prominently thickened ribs, subterete and 6–14-ribbed in sect. Wyomingia, glabrous to sparsely or densely strigose, eglandular; pappus of a single series of barbellate bristles, these sometimes basally caducous, commonly with an outer series setae or scales or these united into an outer corona, the pappus sometimes completely lacking or present only on the ray or disc cypselae. Base chromosome number, x=9. (Greek eri, early, and geron, old man, in allusion to the pappus, which quickly becomes gray, or perhaps in allusion to the solitary, white-woolly heads of some of the alpine species that Linnaeus was familiar with.)

      Lectotype species: Erigeron uniflorus L. (M.L. Green, Prop. Brit. Bot. 181. 1929; W. Huber, Taxon 41:563. 1992 – Herb. Linn., No. 994.23, typ. conserv. prop.) (also see comments in Nesom 1989b).

      About 234 species of Erigeron occur in continental North and Central America, counting 5 that are endemic to Central America south of Mexico and about 165 endemic to North America north of Mexico. An additional 20 occur in the West Indies and 35 in South America. Twenty-eight (28) new species have been added from the United States and Canada since 1947, with several others resurrected from synonymy; 45 species in Mexico have either been described as new (38 species) or transferred from other genera (7 species) to Erigeron over the same period. Of the 91 species of Erigeron found in Mexico, 64 are endemic there, 2 of them are native to Central America or the West Indies, and 25 have part of their range in the United States. When the roughly 100 Old World species are added, the world-wide total for the genus approaches 400 (ca. 389). Nesom (1989c, 1990, 1994a) and Nesom and Noyes (1999) have divided the North and Central American species into 21 sections, emphasizing variation in bud position (nodding, arching-pendant, or erect), lamina behavior (straight, reflexing, or coiling), cypsela morphology, vestiture, inflorescence, habit, and various other features.

      The center of diversity and species abundance for Erigeron is in western North America, and the molecular analysis of Noyes suggests that the evolutionary origin of the genus also is in this area. Cronquist (1947) published his definitive study of the genus in North America north of Mexico, and detailed studies of various species groups have since been published (Nesom 1982, 1989a, 1990a, 1990b, 1992a; Strother & Ferlatte 1988). Secondary centers of diversity in Erigeron are in South America, the Caucasas, the Alps, the Himalayas, and eastern Asia. Morphological accounts of these species are provided in various floristic summaries of varied detail as well as in more focused studies (e.g., Vierhapper 1906; Botschantzev 1959; Solbrig 1962; Pawlowski 1970; Halliday 1976). Native Australian species described as Erigeron have been transferred to other Astereaean genera (Nesom 1994b, 1998), although Forbes and Morris (1996) have maintained the Erigeron pappocromus alliance within Erigeron.

      Nesom (1989b) hypothesized that the genus Trimorpha (Erigeron sect. Trimorpha (Cass.) DC.) is separate from Erigeron, more closely related to Conyza, and provided nomenclatural transfers for North American taxa. It has become clear, however, through studies by Walter Huber and colleagues (Huber 1993; Huber & Leuchtmann 1992; Huber & Nilsson 1995; Huber & Zhang 1991; Oberhδnsli & Huber 1993) that Trimorpha species are closely related to those of sect. Erigeron and that both sections are relatively recently derived within the genus. As suggested by Nesom (1994c) and Huber and Nilsson (1995) and as discussed in detail and experimentally confirmed by Noyes (2000), autogamous breeding systems apparently have arisen independently in a number of Astereaean groups, including Trimorpha and Conyza, where the pistillate florets of a head are greatly increased in number (often outnumbering the bisexual florets), in several series, the inner sometimes reduced to filiform eligulate florets, and the outer with reduced lamina.

      Nesom (1994c) suggested that the four genera of the “Leptostelma group” (Apopyros Nesom, Hysterionica Willd., Leptostelma D. Don, and Neja D. Don), which occur primarily in east-central South America, were relatively primitive within the Conyzinae, perhaps suggesting a point of common origin between the Conyzinae and primarily South American or Southern Hemisphere subtribes. The Leptostelma group is phyletically coherent in the ITS analysis of Noyes (2000), but it apparently shares common ancestry with species of South American Erigeron as well as two sections of Mexican Erigeron, this whole group forming the sister to a major clade that includes western North America species groups, sect. Erigeron and sect. Trimorpha, and the Conyza canadensis group. Molecular data (Noyes 2000) further suggest that the ca. 80 species of American Conyza are polyphyletic and phyletically imbedded within Erigeron. The Conyzinae has proved to be derived from within the broadly inclusive but monophyletic “North American clade” (sensu Noyes & Rieseberg 1999).

      Darwiniothamnus, with three species endemic to the Galapagos Islands, has been treated at generic rank by various authors (e.g., Harling 1962; Cronquist 1971; Lawesson & Adsersen 1987). Nesom (1989c) suggested that Darwiniothamnus is related to the primarily Mexican group Erigeron sect. Cincinnactis Nesom and that the species be maintained within Erigeron. The most recently described species (Lawesson & Adsersen 1987) does not have significant features of the other two upon which the generic concept is based: the plants do not have the strongly shrubby “rosette” habit, the leaves are not in condensed terminal whorls, the heads are not in a condensed-corymbiform capitulescence mostly within the leaves, and the achenes are not dimorphic. The numerous ray florets in several series, with coiling lamina, of D. alternifolius Lawesson & Adsersen are similar to the other two species and also to the species of sect. Cincinnactis. Noyes (pers. comm.) will include material of Darwiniothamnus in his continuing molecular phyletic survey of Conyzinae.

      Perhaps the most remarkable finding to emerge from molecular phylogenetic studies of Erigeron and relatives is that the genus Aphanostephus (which see) apparently has arisen from within the evolutionary matrix of Erigeron and the Conyzinae. The suite of morphological and cytological features characteristic of Aphanostephus led Nesom (1994c) to postulate a close relationship between it and Townsendia, Astranthium, and a group of Southern Hemisphere genera.

      The problems in phylogenetic interpretation tentatively identified in Erigeron s. lat. are similar to those in Machaeranthera (which see), where the origins of the genera Oonopsis and Pyrrocoma appear to be interpolated within the phyletic topology of Machaeranthera. In the analysis of Noyes, subtribe Conyzinae comprises Erigeron, American Conyza, the four genera of the Leptostelma group, and Aphanostephus, but the cladistically basal and terminal taxa of the subtribe are Erigeron. “Strictly speaking, although the Conyzinae form a monophyletic group [with caveats regarding Old World Conyza and one Erigeron species], Erigeron is paraphyletic, as five other genera are derived from within it” (Noyes 2000).

      One American species, Erigeron byei Sundberg & Nesom, is indicated by molecular analyses (Noyes & Rieseberg 1999) to have arisen outside of the Conyzinae. In the original description (Sundberg & Nesom 1990), the species was regarded as most closely related to Erigeron ortegae Blake (= Aster spinosus Benth.) and E. oxyphyllus Greene, but E. oxyphyllus is now accepted as a member of sect. Linearifolii (Nesom 1992a), and E. ortegae has been segregated as the monotypic genus Chloracantha (Nesom et al. 1991). In the protologue of the Chloracantha description, a close similarity in many features was noted between it and Boltonia, and the molecular analysis of Noyes and Rieseberg places E. byei as the sister taxon to Boltonia but not at all closely related to the Conyzinae (Chloracantha was not included in the sample). Erigeron byei has been circumscribed as a monotypic genus (Nesom & Noyes 2000).

      Polyploidy is common among species of Erigeron, and agamospermy apparently is a relatively consistent correlate of polyploidy, especially in odd-polyploid plants. The molecular data of Noyes (2000) indicates that agamospermy has arisen at least three times within the genus, probably more. With hybridization, these phenomena account for the origin of a significant portion of the taxonomic difficulty in the genus. Interactions between ploidal level, breeding systems, and morphological variation have been studied in detail in E. compositus Pursh, a western North American species with diploid, tetraploid, pentaploid, and hexaploid populations (Noyes et al. 1995; Noyes & Soltis 1996).

 

references

 

Botschantzev, V.P. 1959. Erigeron. Flora U.R.S.S. 25:191–288.

Cronquist, A. 1947. A revision of the North American species of Erigeron, north of Mexico. Brittonia 6:121–302.

Cronquist, A. 1971. Compositae. Pp. 300–367 in I.R. Wiggins and D.M. Porter (eds.). Flora of the Galαpagos Islands. Stanford Univ. Press, Stanford, Calif.

Forbes, S.J. and D.I. Morris. 1996. A review of the Erigeron pappocromus Labill. complex. Muelleria 9:175–189.

Halliday, G. 1976. Erigeron. Flora Europaea 4:116–120.

Harling, G. 1962. On some Compositae endemic to the Galαpagos Islands. Acta Horti Berg. Bd. 20, 3:63–120.

Harper, K.T. and R. Van Buren. 1994. Randomly amplified polymorphic DNA and resolution of classification problems in Erigeron (Asteraceae). Amer. J. Bot. [abstract] 81(6):197–198.

Huber, W. 1993. Biosystematisch-okologische Untersuchungen an den Erigeron-Arten (Asteraceae) der Alpen. Verφffentl. Geobot. Inst. ETH, Zurich 114:1–143.

Huber, W. and A. Leuchtmann. 1992. Genetic differentiation of the Erigeron species (Asteraceae) in the Alps: a case of unusual allozymic uniformity. Pl. Syst. Evol. 183:1–16.

Huber, W. and O. Nilsson. 1995. Close genetic affinity of northern and other Eurasiatic Erigeron species. Pp. 197–222 in D.J.N. Hind, C. Jeffrey, and G.V. Pope (eds.). Advances in Compositae Systematics, Royal Botanic Gardens, Kew.

Huber, W. and H. Zhang. 1991. Morphologische und chemotaxonomische untersuchungen an den Erigeron-Arten der Alpen. Ber. Geobot. Inst. ETH, Zurich 57:116–164.

Lawesson, J.E. and H. Adsersen. 1987. Notes on the endemic genus Darwiniothamnus (Asteraceae-Astereae) from the Galαpagos Islands. Opera Bot. 92:7–15.

Nesom, G.L. 1982. Systematics of the Erigeron rusbyi group (Asteraceae) and delimitation of section Peregrinus. Syst. Bot. 7:457–470.

Nesom, G.L. 1989a. Taxonomy of Erigeron sect. Polyactis (Compositae: Astereae). Phytologia 66:415–455.

Nesom, G.L. 1989b. The separation of Trimorpha (Compositae: Astereae) from Erigeron. Phytologia 67:61–66.

Nesom, G.L. 1989c. Infrageneric taxonomy of New World Erigeron (Compositae: Astereae). Phytologia 67:67–93.

Nesom, G.L. 1990a. Taxonomy of the Erigeron pringlei group (Asteraceae: Astereae). Phytologia 69:227–235.

Nesom, G.L. 1990b. Taxonomy of the Erigeron coronarius group of Erigeron sect. Geniculactis (Asteraceae: Astereae). Phytologia 69:237–253.

Nesom, G.L. 1992a. Revision of Erigeron sect. Linearifolii (Asteraceae: Astereae). Phytologia 72:157–208.

Nesom, G.L. 1992b. Taxonomic notes on Erigeron (Asteraceae: Astereae) of California, Nevada, and Arizona. Phytologia 73:186–202.

Nesom, G.L. 1994a. Erigeron pattersonii (Asteraceae: Astereae), a new species from Nuevo Leon, Mexico. Phytologia 76:96–100.

Nesom, G.L. 1994b. Taxonomic dispersal of Australian Erigeron (Asteraceae: Astereae). Phytologia 76:143–159.

Nesom, G.L. 1994c. Subtribal classification of the Astereae (Astereae). Phytologia 76:193–274.

Nesom, G.L. 1998 [2000]. Full constitution of the Australian genus Pappochroma (Asteraceae: Astereae). Phytologia 85:276-279.

Nesom, G.L. and R.D. Noyes. 1999. Notes on sectional delimitations in Erigeron (Asteraceae: Astereae). Sida 18:1161–1165.

Nesom, G.L., Y. Suh, D.R. Morgan, S.D. Sundberg, and B.B. Simpson. 1991. Chloracantha, a new genus of American Astereae (Asteraceae). Phytologia 70:371–381.

Noyes, R.D. 2000. Biogeographical and evolutionary insights on Erigeron and allies (Asteraceae) from ITS sequence data. Pl. Syst. Evol. 220:93–114.

Noyes, R.D. and L.H. Rieseberg. 1999. ITS sequence data support a single origin of North American Astereae (Asteraceae) and reflect deep geographic divisions in Aster s.l. Amer. J. Bot. 86:398–412.

Noyes, R.D., D.E. Soltis, and P.S. Soltis. 1995. Genetic and cytological investigations in sexual Erigeron compositus (Astereaceae). Syst. Bot. 20:132–146.

Noyes, R.D. and D.E. Soltis. 1996. Genotypic variation in agamospermous Erigeron compositus (Asteraceae). Amer. J. Bot. 83:1292–1303.

Oberhδnsli, T, and W. Huber. 1993. Zur Chemotaxonomie Erigeron-Arten (Compositae) der Alpen. Ber. Geobot. Inst. ETH, Zurich 59:124–136.

Pawlowski, B. 1970. De speciebus polonicis et carpaticis generis Erigeron L. Fragm. Florist. Geobot. 16:255–293.

Reed, S.L. 1996. Genetic variation and population structure in four rare species of Erigeron (Asteraceae) from the American Southwest. M.S. thesis, Univ. of New Mexico, Albuquerque.

Solbrig, O.T. 1962. The South American species of Erigeron. Contr. Gray Herb. 191:3–79.

Spongberg, S.A. 1971. A systematic and evolutionary study of North American arctic and alpine monocephalous species of Erigeron (Compositae). Ph.D. diss., Univ. of North Carolina, Chapel Hill.

Strother, J.L. and W.J. Ferlatte. 1988. Review of Erigeron eatonii and allied taxa (Compositae: Astereae). Madrono 35:77–91.

Sundberg, S.D. and G.L. Nesom. 1990. A new species of Erigeron (Asteraceae: Astereae) from Chihuahua, Mexico. Phytologia 69:278–281.

Utelli, A.B., W. Huber, and H.J. Zopfi. 1995. Phenotypic plasticity in alpine Erigeron species (Asteraceae). Nordic J. Bot. 15:483–492.

Valdebenito, H., T.F. Stuessy, D.J. Crawford, and O.M. Silva. 1992. Evolution of Erigeron (Compositae) in the Juan Fernandez Islands, Chile. Syst. Bot. 17:470–480.

Vierhapper, F. 1906. Monographie der alpinen Erigeron-Arten Europas und Vorderasiens. Beih. Bot. Centralbl. 19, Abt. 2:285–560.

 

36. EUCEPHALUS Nutt., Trans. Amer. Philos. Soc. 2, 7:298. 1841.

 

Aster subsect. Eucephalus (Nutt.) Benth. in Benth. & J.D. Hook., Gen. Pl. 2:273. 1873.

Aster sect. Eucephalus (Nutt.) Munz & Keck ex A.G. Jones, Brittonia 32:236. 1980.

 

Perennials usually from creeping rhizome, rarely taprooted, the stems mostly simple or few-branched until the inflorescence, 2–15 dm tall, arising directly from the rhizome without a evident caudex, glabrous or sparsely pilose with thin-based hairs to closely tomentose, minutely glandular under the heads. Leaves all cauline, the lowermost scale-like, large and relatively even-sized and evenly arranged above, 1.5–11 cm long, sessile, not clasping (or slightly subclasping), entire, sometimes 3-nerved. Heads mostly 6–20 and corymboid, sometimes loosely so, sometimes solitary; involucres campanulate to hemispheric, 6–10 mm high; phyllaries in 4–6 graduated series, ovate to lanceolate, often convex, distinctly keeled from base to tip, stramineous-indurate, relatively even textured, the margins (inner series) thin-hyaline, often purplish distally, without a distinct apical patch but the apical area sometimes green. Ray florets pistillate, fertile, 6–20 or 0(–5) in some species, white to bluish, slightly coiling. Disc corollas perfect, fertile, yellow, the lobes deltate and erect to triangular and reflexing; style branches with linear-lanceolate collecting appendages. Cypselae obovate, ca. 1.5–3 mm long, strongly flattened with a pair of lateral nerves, sometimes with 1–2 additional nerves on each face, eglandular; pappus of terete bristles usually dilated at the apex, in 2–3 series, all of equal length or the outer sometimes markedly shorter. Base chromosome number, x=9. (Greek, eu-, good or original, kephalotos, with a head, referring to the aesthetic qualities of the heads, as Nuttall was struck by their beauty in at least the type species. “The name alludes to the elegant appearance of the calyx.” – Nuttall 1841)

Lectoype species (Jones 1980): Eucephalus elegans Nutt.

      A genus of 11 species distributed primarily in California and nearby areas of the northwestern United States and adjacent Canada. Eucephalus is a morphologically coherent group (needing a modern taxonomic summary), recognized particularly by its scale-like lower cauline leaves, corymboid inflorescence, broad, strongly keeled phyllaries without a sharply delimited apical patch, flattened, obovate, eglandular cypselae, and multiseriate pappus of apically dilated bristles. The rayless Californian species E. breweri (A. Gray) Nesom was previously transferred from Chrysopsis and placed by Semple (1988) among the species of Eucephalus (as a subgenus of Aster). The discoid condition also occurs in E. vialis Bradshaw, E. brickellioides (Greene) Nesom, and E. glabratus (Greene) Greene, although the latter two species may sometimes produce 1–5 ray florets. Molecular evidence apparently suggests that Aster glaucodes Blake is a species of Eucephalus (Xiang & Semple 1996) but morphological features refer it to Eurybia (Nesom 1994).

 

references

 

Jones, A.G. 1980. A classification of the New World species of Aster (Asteraceae). Brittonia 32:230–239.

Nesom, G.L. 1994. Review of the taxonomy of Aster sensu lato (Asteraceae: Astereae), emphasizing the New World species. Phytologia 77:141–297.

Nuttall, T. 1841. Descriptions of new species and genera of plants in the natural order of the Compositae, collected ... during the years 1834 and 1835. Trans. Amer. Philos. Soc. 2, 7:283–453.

Semple, J.C. 1988. Aster breweri: A new combination for a rayless Aster based on Chrysopsis breweri (Compositae: Astereae). Syst. Bot. 13:538–546.

Xiang, C. and J.C. Semple. 1996. Molecular systematic study of Aster s. lat. and related genera (Asteraceae: Astereae) based on chloroplast DNA restriction site analyses and mainly North American taxa. In D.J.N. Hind and H.J. Beentje (eds.). Compositae: Systematics. Vol. 1, pp. 393–423. Proc. Interntl. Compositae Conf., Kew, 1994.

 

37. EURYBIA (Cass.) S.F. Gray, Nat. Arrang. Brit. Pl. 2:464. 1821.

 

Aster subg. Eurybia Cass., Bull. Soc. Philom. (Paris) 1818:166. 1818.

Aster sect. Radulini (Rydb.) A.G. Jones, Brittonia 32:237. 1980.

Aster subg. Calliastrum Torr. & A. Gray, Fl. N. Amer. 2:106. 1841.

Aster sect. Calliastrum (Torr. & A. Gray) Benth. in Benth. & Hook., Gen. Pl. 2:271. 1873.

Aster sect. Spectabiles A. Gray, Synopt. Fl. 1(2):175. 1884.

Aster subg. Biotia DC. ex Torr. & A. Gray, Fl. N. Amer. 2:104. 1841.

Aster subsect. Biotia (DC. ex Torr. & A. Gray) Semple, Phytologia 58:429. 1984.

Biotia DC., Prodr. 5:264. 1836 [nom. illeg., non Biotia Cass.].

Leiachenis Raf., Fl. Tellur. 2:45. 1836 [1837].

Herrickia Woot. & Standl., Contr. U.S. Natl. Herb. 16:186. 1913.

Heleastrum DC., Prodr. 5:263. 1836.

Aster subg. Heleastrum (DC.) A. Gray, Proc. Amer. Acad. Arts 16:97. 1880.

Weberaster Lφve & Lφve, Taxon 31:359. 1982.

 

Perennial herbs, producing short, thick rhizomes and/or long, slender, scale-leaved rhizomes, stems variously branched, 1–12 dm tall, the stems and leaves mostly glabrate, stipitate-glandular in a few species. Leaves linear to obovate or cordate, usually with 3–5 veins entering in parallel from the base, sessile, entire to serrate or spinulose. Heads in a compact to loose, corymboid inflorescence, rarely reduced to 1-several heads; involucres turbinate to campanulate, 4–12 mm high; phyllaries in 5–7 graduated series, basally indurate with a sharply demarcated green apical patch, usually distinctly low-keeled, the margins usually minutely ciliate-fringed; receptacles commonly foveolate, without chaff. Ray florets pistillate, fertile, blue and coiling at maturity or white and little coiling. Disc florets perfect, fertile, narrowly tubular or long-tubed and abruptly ampliate in the distal third, purpling with maturity; style branches with linear-triangular collecting appendages. Cypselae cylindric or subcylindric, (2–)3–5(–7) mm long, 8–12(–18) nerved, eglandular; pappus (1–)2-seriate, of equal-length barbellate bristles, these often stiff and flattened, often apically dilated. Base chromosome number, x=9. (Greek, eurys, wide or widespread, baios, few, perhaps referring to the few, wide-spreading ray florets; Cassini did not explain the meaning of the name.)

      Lectotype species (Nesom 1994): Eurybia divaricata (L.) Nesom

      A genus of 28 species consolidated from a number of species groups within North American Aster s. lat. (Nesom 1994). A discussion of the application of the generic name is given by Nesom (1994). Eurybia is distributed in eastern and western North America, with one species reaching northward into Alaska, across the Aleutians, and into northeastern Asia. The genus is distinctive in its combination of corymboid inflorescence, ciliate-fringed, rounded phyllaries with a green, often basally truncate apical patch, linear-lanceolate disc style appendages, cylindric and multinerved cypselae, 2-seriate pappus of equal-length, apically thickened bristles, and base chromosome number of x=9. Sericocarpus, perhaps the closest relative of Eurybia, also is distributed in both eastern and western North America and is similar in other respects, but it has punctate- or sessile-glandular leaves, glomerate heads with white ray and disc corollas, obconic and sericeous cypselae, and a different chromosome morphology.

      The species of Eurybia and Sericocarpus were maintained by Xiang and Semple (1996) and Semple et al. (1996) within Aster s. str. as North American species closely related to the typical Old World element of the genus. Further data (Noyes & Rieseberg 1999) support the view that New World asters are cladistically distinct from those of the Old World and render the combined molecular data somewhat equivocal.

      Eurybia is divided into two subgenera and eight sections (Nesom 1994). The species of “grass-leaved asters,” endemic to the southeastern US, have been recognized at as subg. Heleastrum (DC.) Nesom; the other species constitute subg. Eurybia. Some species groups have distributions concentrated in either the eastern or western US, while others are more widespread. The monotypic genus Herrickia of the southwestern US is treated, with inclusion of three other morphologically and geographically coherent species, as Eurybia sect. Herrickia (Woot. & Standl.) Nesom. The cpDNA analysis of Xiang and Semple (1996) places Aster glaucodes Blake within Eucephalus, but as observed earlier (Nesom 1994), the morphological features of this species appear to be most similar to those of Eurybia sect. Herrickia. Eurybia (Aster) integrifolia (Nutt.) Nesom of the northwestern US is isolated within the genus and is treated as the monotypic sect. Integrifoliae Nesom. Molecular data (Xiang & Semple 1996) indicate that this species may be only distantly related to Eurybia.

 

references

 

Lamboy, W.F. 1987. Aster section Biotia (Asteraceae) in New England USA and the status of Aster glomeratus. Rhodora 89:299–318.

Lamboy, W.F. 1988. The status of Aster commixtus and a new species of Aster from the southeastern United States. Syst. Bot. 13:187–195.

Lamboy, W.F. and A.G. Jones. 1987. Lectotypifications and neotypifications in Aster section Biotia (Asteraceae), including a complete annotated synonymy. Brittonia 39:286–297.

Lamboy, W.F., D.L. Nickrent, and A.G. Jones. 1991. Isozyme evidence and phenetic relationships among species in Aster section Biotia (Asteraceae). Rhodora 93:205–225.

Nesom, G.L. 1994. Review of the taxonomy of Aster sensu lato (Asteraceae: Astereae), emphasizing the New World species. Phytologia 77:141–297.

Noyes, R.D. and L.H. Rieseberg. 1999. ITS sequence data support a single origin of North American Astereae (Asteraceae) and reflect deep geographic divisions in Aster s.l. Amer. J. Bot. 86:398–412.

Semple, J.C., S.B. Heard, and C.S. Xiang. 1996. The Asters of Ontario (Compositae: Astereae): Diplactis Raf., Oclemena E.L. Greene, Doellingeria Nees and Aster L. (including Canadanthus Nesom, Symphyotrichum Nees, and Virgulus Raf.). Rev. ed. Univ. of Waterloo Biol. Ser. 38:i–viii, 1–94.

Xiang, C. and J.C. Semple. 1996. Molecular systematic study of Aster s. lat. and related genera (Asteraceae: Astereae) based on chloroplast DNA restriction site analyses and mainly North American taxa. In D.J.N. Hind and H.J. Beentje (eds.). Compositae: Systematics. Vol. 1, pp. 393–423. Proc. Interntl. Compositae Conf., Kew, 1994.

 

38. EUTHAMIA Nutt. ex Cass. in Cuvier, Dict. Sci. Nat. 37:471. 1825 (see Nesom 1999).

 

Euthamia (Nutt.) Nutt., Trans. Amer. Philos. Soc. ser. 2, 7:325. 1841. (nom. superfl.)

Solidago sect. Euthamia Nutt., Gen. N. Amer. Pl. 2:162. 1818.

Solidago sect. Euthamia (Nutt.) DC., Prodr. 5:341. 1836. (nom. superfl.)

Solidago subg. Euthamia (Nutt.) House, Bull. New York State Mus. 254:694. 1924.

Erigeron sect. Submultiflori G. Don in Loudon, Hort. Brit. 343. 1830.

 

Herbaceous perennials, rhizomatous, essentially glabrous or sometimes scabridulous in the inflorescence and leaf margins and veins of lower surfaces, the stems 4–8(–12) dm tall, branched in the upper part. Leaves alternate, sessile, linear to linear-lanceolate, 3–13 cm long, 1–3(–5) veined, entire, all cauline, mostly even-sized, punctate and usually at least slightly resinous. Heads short-pedunculate to sessile, often in glomerate clusters, the whole inflorescence a distinctly flat corymb (rounded in E. occidentalis Nutt.); involucres cylindric to turbinate or hemispheric, 3–6 mm high; phyllaries in 3–5 graduate series, ovate to oblong, obtuse, mostly chartaceous, glutinous in some, with a restricted, greenish, thickened apical region; receptacle deeply foveolate, at least somewhat fimbrillate. Ray florets 15–25, pistillate, fertile, the lamina yellow, mostly 2–4 mm long. Disc florets (2–)7–15(–20), perfect, fertile, the corollas ampliate-tubular, the lobes triangular; style branches with lanceolate collecting appendages. Cypselae oblong to narrowly turbinate, 1–1.5 mm long, subterete, with 2–4 very faint nerves, strigose; pappus a single series of barbellate bristles. Base chromosome number, x=9. (Greek, eu-, well, and -thamees, crowded, "in allusion to the crowding of the flower heads." – Nuttall 1818)

      Type species: Chrysocoma graminifolia L. (= Euthamia graminifolia (L.) Nutt.).

      In the only comprehensive treatment of Euthamia, Sieren (1981) recognized eight species. Other contemporary botanists have proposed to reduce the number to five or six but no one has published a comprehensive update, and taxonomic problems remain. All species are restricted to the central and eastern United States except one, E. occidentalis Nutt., which occurs widely over the western US, southwestern Canada, and into Baja California, Mexico. Euthamia is recognized by its rhizomatous habit, narrow, punctate, cauline leaves, glomerate or short-pedicellate clusters of small, yellow-rayed heads in distinct corymbs, and small, terete cypselae with a pappus of barbellate bristles. The genus has been discussed in the context of a putatively close relationship with Solidago (Kapoor & Beaudry 1966; Anderson & Creech 1975) and most of the species have names in that genus; differences between Solidago and Euthamia were summarized by Cronquist (1980). Summaries of recent molecular evidence (Nesom et al. 1989; Lane et al. 1996) indicate that Euthamia is more closely related to Bigelowia, Gymnosperma, and Gutierrezia and related genera than it is to Solidago. Nomenclatural complexities in the genus have recently been reviewed (Reveal 1991; Gandhi 1999; Nesom 1999).

 

references

 

Anderson, L.C. and J.B. Creech. 1975. Comparative leaf anatomy of Solidago and related Asteraceae. Amer. J. Bot. 62:486–493.

Cassini, H. 1825. Euthamia. Dict. Sci. Nat. 37:470–472.

Croat, T.B. 1970. Studies in Solidago. I. The Solidago graminifolia – S. gymnospermoides complex. Ann. Missouri Bot. Garden 57:250–251.

Cronquist, A. 1980. Euthamia. Pp. 134–136 in Vascular flora of the southeastern United States, Vol. I. Asteraceae. Univ. of North Carolina Press, Chapel Hill.

Gandhi, K. 1999. Nomenclatural novelties for the Western Hemisphere plants–II. Harvard Pap. Bot. 4:295–299.

Johnson, M.F. 1991. Observations on the trichomes of Euthamia and Solidago (Asteraceae): A scanning electron microscopy study. Amer. J. Bot. [abstract] 78(6):194–195.

Kapoor, B.M. and J.R. Beaudry. 1966. Studies on Solidago. VII. The taxonomic status of the taxa Brachychaeta, Brintonia, Chrysoma, Euthamia, Oligoneuron, and Petradoria in relation to Solidago. Canad. J. Genet. Cytol. 8:422–443.

Lane, M.A., D.R. Morgan, Y. Suh, B.B. Simpson, and R.K. Jansen. 1996. Relationships of North American genera of Astereae, based on chloroplast DNA restriction site data. In D.J.N. Hind and H.J. Beentje (eds.). Compositae: Systematics. Vol. 1, pp. 49–77. Proc. Interntl. Compositae Conf., Kew, 1994.

Nesom, G.L. 1999. Review of early nomenclature in Euthamia (Asteraceae: Astereae). Sida 18:1009-1018.

Nesom, G.L., Y. Suh, D. Morgan, and B. Simpson. 1989. Xylothamia (Compositae: Astereae), a new genus related to Euthamia. Sida 14:101–116.

Reveal, J.L. 1991. Erigeron carolinianus L., an earlier name for Euthamia (Solidago) tenuifolia (Pursh) E. Greene (Asteraceae). Taxon 40:505–508.

Semple, J.C., G.S. Ringius, C. Leeder, and G. Morton. 1984. Chromosome numbers of goldenrods, Euthamia and Solidago (Compositae: Astereae). II. Additional counts with comments on cytogeography. Brittonia 36:280–292.

Sieren, D.J. 1981. The taxonomy of the genus Euthamia. Rhodora 83:551–579.

Taylor, C.E.S. and R.J. Taylor. 1983. New species, new combinations and notes on the goldenrods (Euthamia and Solidago – Asteraceae). Sida 10:176–183.

 

39. GEISSOLEPIS B.L. Rob., Proc. Amer. Acad. Arts 27:177. 1892.

 

Perennial, succulent, prostrate herbs with creeping, fibrous-rooted stolons, these quickly becoming woody, the stems and peduncles sparsely pilose, glabrescent. Leaves alternate, linear-oblanceolate, 6–25 mm long, succulent, sparsely strigose along the midvein on the upper side, otherwise glabrous. Heads solitary on thick, bracteate, erect, axillary peduncles 1–3 cm long; involucres broadly turbinate, 6–8 mm wide; phyllaries 4–5 seriate, thick, strongly graduate in length; receptacles steeply conical, paleate, the pales obovate, obtuse to rounded at the apex, with thick, apical cilia, the midvein resinous, sometimes expanded apically. Ray florets pistillate, fertile, 8–12, the lamina white, obovate to broadly obovate, not reflexing or coiling. Disk florets perfect, fertile, the corollas orange-yellow with thick, resinous, orange veins, funnelform, gradually ampliate, 2.8–3.5 mm long; style branches with triangular collecting appendages. Cypselae obovate-triangular, 1.2–1.5 mm long, plump, slightly compressed or the outer 3–4-angled, strigose with long, apically bifurcate and hooked trichomes, with ca. 8, thick, light-colored ribs, these usually expanded into yellow-orange resin pockets near the apex; pappus of 6–8, separate, narrowly triangular scales 0.8–1 mm long, the margins with uncinate cilia. Base chromosome number, x=8 or 9, reported as 2n=16 (Ralston et al. 1989) and 2n=18 (Lane and Li 1993). (“The generic name, derived from [Greek] geisson [eaves, or border] and lepis [scale], has reference to the well imbricated scales of the involucre, one of the distinctive characters of the genus.” – Robinson 1892)

      Type species: Geissolepis suaedifolia B.L. Rob.

      A monotypic genus known only from a few small populations in the vicinity of Rio Verde in central San Luis Potosν, Mexico, where it grows on erosion-exposed gypsum and gypseous alkaline flats. Its chances of remaining extant appear to be small. Geissolepis is distinct in its combination of a prostrate, succulent habit, strongly developed resin canals on the phyllaries, cypselae, and disc corollas, turbinate heads, steeply conical, chaffy receptacles, ray corollas with white, broadly obovate lamina, short, gradually ampliate disc corollas, achenial trichomes with bifurcate, sharply hooked apices, and pappus of scales with uncinate-ciliate margins. The genus was assigned in its original description to the tribe Heliantheae subtribe Madiinae. Later, however, Robinson and Brettell (1972) followed by Nesom (1994) have noted that its proper position is in the Astereae, where it is similar to Astranthium and Aphanostephus in its conical receptacles and glochidiate achenial trichomes. Molecular data of Noyes and Rieseberg (1999) place Geissolepis close to Astranthium but not in a strictly monophyletic relationship.

 

references

 

Lane, M.A. and J. Li. 1993. Chromosome number reports in Compositae with emphasis on tribe Astereae of the southwestern United States and Mexico. Sida 15:539–546.

Nesom, G.L. 1994. Subtribal classification of the Astereae (Asteraceae). Phytologia 76:193–274.

Noyes, R.D. and L.H. Rieseberg. 1999. ITS sequence data support a single origin of North American Astereae (Asteraceae) and reflect deep geographic divisions in Aster s.l. Amer. J. Bot. 86:398–412.

Ralston, B., G. Nesom, and B.L. Turner. 1989. Chromosome numbers in Mexican Asteraceae with special reference to the tribe Tageteae. Sida 13:359–368.

Robinson, B.L. 1892. Descriptions of new plants collected in Mexico by C.G. Pringle in 1890 and 1891, with notes upon a few other species. Proc. Amer. Acad. Arts 27:165–185.

Robinson, H. and B.D. Brettell. 1972. The relationship of Geissolepis. Phytologia 24: 299–301.

 

40. GRINDELIA Willd., Ges. Naturf. Freunde Berlin Mag. 1:259. 1807.

 

Prionopsis Nutt., Trans. Amer. Philos. Soc. 2, 7:329. 1841.

Haplopappus sect. Prionopsis (Nutt.) A. Gray, Smithsonian Contr. Knowledge 3(2):98 [Pl. Wright. 1:98]. 1852.

 

Annual, biennial, or perennial herbs 1–18 dm tall, sometimes suffruticose, taprooted, less commonly rhizomatous, stoloniferous in G. oolepis Blake, often resinous from sunken, punctate glands, sometimes stipitate-glandular, sometimes without glands or apparent punctations. Leaves alternate, short-petiolate to sessile, often clasping, mostly oblong to oblanceolate or oblong-lanceolate, 1–22 cm long, entire to toothed or pinnatifid, the margins closely serrulate-dentate with aristate or gland-tipped teeth. Heads solitary or (uncommonly) loosely corymboid; involucres campanulate to hemispheric or cupulate, 5–17 mm high, with a marked impression at the peduncle insertion; phyllaries in 4–8 series, usually whitish-sclerified at the base, erect to spreading or reflexed or coiling; receptacles alveolate to foveolate. Ray florets present or absent, pistillate, fertile, yellow to orange. Disc florets perfect, fertile or with sterile ovaries, sometimes only the inner with sterile ovaries, the corollas tubular, most often with an abruptly ampliate throat, the lobes triangular; style branches with linear-lanceolate to ovate-oblong collecting appendages. Cypselae glabrous, dimorphic or monomorphic, the outer commonly with thick walls, smooth to deeply sculptured, compressed to subquadrate, [winged in G. chiloensis (Cornel.) Cabrera and close relatives, coronate in G. brachystephana Griseb. and others], 2.5–5 mm long, the inner similar to the outer or strongly flattened and with numerous, thin, superficial, longitudinal nerves; pappus in most North American species of 2–4 slender to broad, white, basally caducous awns with smooth to setulose margins, inserted inside the perimeter of the flat or concave cypsela apex (awns up to 18 in some South American species; in G. papposa Nesom & Suh, very numerous, in 2–4 series, of uneven length and thickness, the inner thicker, and sometimes basally connate and deciduous in a ring). Base chromosome number, x=6. (For Russian botanist David Hieronymus Grindel, 1776–1836.)

      Type species: Grindelia inuloides Willd.

      A genus of about 70 species distributed primarily in North America (28 in the United States and an additional 17 Mexican species that do not occur in the US); 25 species have differentiated in South America (Bartoli and Tortosa 1999). A number of species show formally recognized infraspecific variation. Grindelia is recognized by its taprooted (usually) habit, spinulose- or glandular-toothed leaves, usually long-peduncled, solitary heads, goblet-shaped cypselae, glandular-punctate and resinous, blocky, thick-walled cypselae with relatively few, flattened, basally caducous, bristle-like awns, and base chromosome number of x=6. In some species (e.g., the Mexican G. nelsonii Steyerm.), the heads may be numerous in a loosely corymboid inflorescence. The South American G. chiloensis and its close relatives (Bartoli and Tortosa 1994) are unusual in their winged cypselae and rhizomatous (or branching caudex) habit. Steyermark (1934) distinguished species of Grindelia emphasizing features of vestiture, phyllaries, and cypsela and pappus morphology; features of the roots and foliar teeth also have proved to be of taxonomic significance.

      The South American species Haplopappus pectinatus Phil. was transferred to Grindelia after observation that it forms fertile hybrids with another species long accepted in Grindelia (Bartoli & Tortosa 1998b). The persistent pappus of numerous bristles in H. pectinatus is similar to that of the monotypic North American genus Prionopsis (P. ciliata (Nutt.) Nutt. = Haplopappus ciliatus (Nutt.) DC. = Grindelia ciliata (Nutt.) Spreng.), which also was recently moved within the bounds of Grindelia (Nesom et al. 1993). Grindelia prunelloides (Less.) Bartoli & Tortosa also has many (38–50), basally united bristles. The pappus elements of G. papposa vary from slender barbellate bristles to thicker and flattened awns with short-ciliate margins, the latter like those typical of most of the genus.

 

references

 

Bartoli, A. and R.D. Tortosa. 1994. Tres nuevas especies de Grindelia (Asteraceae) afines a G. chiloensis (Corn.) Cabrera. Kurtziana 23:131–150.

Bartoli, A., R.D. Tortosa, y G.H. Rua. 1995. Una nueva especie de Grindelia (Asteraceae) de Uruguay. Hickenia 2:119–122.

Bartoli, A., R.D. Tortosa, and E. Marchesi. 1996. Two new species of Grindelia (Astereae, Asteraceae) from Uruguay. Brittonia 48:75–78.

Bartoli, A. and R.D. Tortosa. 1998a. Estudios cromosσmicos en especies sudamericanas de Grindelia (Astereae, Asteraceae). Kurtziana 26:165–171.

Bartoli, A. and R.D. Tortosa. 1998b. Intermediacy between Grindelia chiloensis and Haplopappus pectinatus (Astereae, Asteraceae). Taxon 47:337–345.

Bartoli, A. and R.D. Tortosa. 1998c. Grindelia mendocina (Asteraceae, Astereae), a new South American species. Brittonia 50:497–499.

Bartoli, A. and R.D. Tortosa. 1999. Revisiσn de las especies sudamericanas de Grindelia (Asteraceae: Astereae). Kurtziana 27:327–359.

Baskin, J.M. and C.C. Baskin. 1979. Studies on the autecology and population biology of the monocarpic perennial Grindelia lanceolata. Amer. Midl. Nat. 102:290–299.

Cabrera, A.L. 1931. Revisiσn de las especies sudamericanas del gιnero Grindelia. Revista Mus. La Plata, Secc. Bot. 33:207–249.

Dunford, M.P. 1964. A cytogenetic analysis of certain polyploids in Grindelia (Compositae). Amer. J. Bot. 51:49–56.

Dunford, M.P. 1970. Interchange heterozygosity in diploid interspecific hybrids in Grindelia (Compositae). Amer. J. Bot. 57:623–628.

Dunford, M.P. 1986. Chromosome relationships of diploid species of Grindelia (Compositae) from Colorado, New Mexico, and adjacent areas, U.S.A. Amer. J. Bot. 73:297–303.

Hall, H.M. 1928. The genus Haplopappus – A phylogenetic study in the Compositae. Section 3. Prionopsis. Carnegie Inst. Washington Publ. No. 389:33–34, 84–86.

Lane, M.A. 1992. New combinations in Californian Grindelia (Compositae: Astereae). Novon 2:215–217.

Nesom, G.L. 1990. Studies in the systematics of Mexican and Texan Grindelia (Compositae: Astereae). Phytologia 68:303–332.

Nesom, G.L. 1992a. Grindelia villarrealii (Asteraceae: Astereae), a new species from northeastern Mexico. Phytologia 73:264–266.

Nesom, G.L. 1992b. Species rank for the varieties of Grindelia microcephala (Asteraceae: Astereae). Phytologia 73:326–329.

Nesom, G.L., Y. Suh, and B.B. Simpson. 1993. Prionopsis (Asteraceae: Astereae) united with Grindelia. Phytologia 75:341–346.

Steyermark, J.A. 1934. Studies in Grindelia. II. A monograph of the North American species of the genus Grindelia. Ann. Missouri Bot. Gard. 21:433–608.

Whitaker, T.W. and J.A. Steyermark. 1935. Cytological aspects of Grindelia species. Bull. Torrey Bot. Club 62:69–73.

 

41. GUNDLACHIA A. Gray, Proc. Amer. Acad. Arts 16:100. 1880.

 

Shrubs to 2 m tall, branching from the base. Leaves arranged evenly on stems or clustered at the tips, linear to linear-lanceolate, spatulate, or obovate, 1–8 cm long, entire or denticulate, apically acute to obtuse, punctate and usually resinous. Heads in clusters of 1–5, these clusters in racemes or corymbs, in turn borne in panicles or flat-topped to slightly rounded corymbs; involucres cylindric to narrowly obconic, 3–6 mm high, resinous; phyllaries in 3–5 graduated series, linear-lanceolate to ovate, with an orange-resinous midvein, basally white-indurate, green at the apex; receptacles foveolate to alveolate. Ray florets pistillate, fertile, 3–8, white, the limb 2–3.5 mm long. Disc florets perfect, fertile, 3–10, white, funnelform, 4–5.5 mm long, the lobes lanceolate, laxly erect to recurved; style branches with lanceolate, papillate collecting appendages. Cypselae cylindric, 1–2.5 mm long, 5-nerved, sparsely pilose; pappus a single series of even-length, barbellate bristles. Base chromosome number, x=9. (“Dedicated to Mr. J. Gundlach of Havana, an acute naturalist, the friend and companion of Charles Wright in his Cuban explorations.” – Gray 1880)

      Type species: Gundlachia domingensis (Spreng.) A. Gray.

      A genus of two species (including a total of seven taxa, in the concept of Lane 1996) essentially endemic to the Greater and Lesser Antilles and the Bahamas. Gundlachia corymbosa (Urb.) Britton ex Bold has six varieties; G. domingensis is monotypic. All of the taxa occur on Cuba and Hispaniola, with G. corymbosa var. corymbosa spread through the rest of the islands and at least one locality on the coast of northern Venezuela. Gundlachia is recognized by its shrubby habit, punctate leaves, small, clustered, white-rayed heads in panicles or corymbs, and cylindric cypselae with a 1-seriate pappus. It is the only genus of Astereae essentially endemic to the West Indies. Several subgroups of Erigeron are the only other Astereaean groups to have radiated evolutionarily on these islands.

      Lane (1996) has hypothesized that the sister taxon of Gundlachia is the monotypic Gymnosperma (x=8) of the southwestern USA and Mexico, noting similarities between them in various features. Nesom (1993, 1994) has suggested that Gundlachia is most closely related to genera of the southeastern United States, particularly Chrysoma, Bigelowia, and Euthamia. Much earlier, Greene (1895) also observed similarities between Gundlachia and Chrysoma and formally enlarged the latter to include the former.

 

references

 

Gray, A. 1880. Contributions to North American botany. I. Notes on some Compositae. Proc. Amer. Acad. Arts 16:78–102.

Greene, E.L. 1895. Observations on the Compositae. – VIII. Erythea 3:6–15.

Lane, M.L. 1996. Taxonomy of Gundlachia (Compositae: Astereae). Brittonia 48:532–541.

Nesom, G.L. 1993. Taxonomic infrastructure of Solidago and Oligoneuron (Asteraceae: Astereae) and comments on their phylogenetic position. Phytologia 75:1–44.

Nesom, G.L. 1994. Subtribal classification of the Astereae (Asteraceae). Phytologia 76:193–274.

 

42. GUTIERREZIA Lag., Gen. Sp. Pl. [Elench. Hort. Matriti] 30. 1816.

 

Brachyris Nutt., Gen. Amer. Pl. 2:163. 1818.

Odontocarpha DC., Prodr. 5:71. 1836.

Hemiachyris DC., Prodr. 5:313. 1836.

Greenella A. Gray, Proc. Amer. Acad. Arts 16:81. 1880.

 

Annuals or perennials, herbaceous to woody, usually without a basal rosette at flowering, 1–15(–20) cm tall. Leaves alternate, decurrent, linear to lanceolate or spatulate, 1–10 cm long, surfaces punctate and glutinous, glabrous or minutely pubescent, margins entire, sometimes scabrous-ciliate. Heads solitary or in clusters of 3–6, radiate (discoid in 1 sp.); involucres cylindric to campanulate, 2–11.5 mm high; phyllaries in 2–4 imbricated series, stramineous, 1- or 3-nerved, bases white-indurate; receptacles flat to conical or columnar, alveolate, with numerous, uniseriate, swollen, apically hooked trichomes. Ray florets pistillate, fertile, 1–30 (absent in 1 sp.), corollas yellow or white, coiling upon maturity. Disc florets perfect, fertile, the corollas concolorous with the rays, lobes short-deltate and erect; style branches with linear-lanceolate collecting appendages. Cypselae light tan to purplish-black, clavate or cylindrical, 0.5–3.5 mm long, multi-nerved, pubescent (essentially glabrous in 1 species), the trichomes white, usually arising primarily from between the ribs and appearing to occur in longitudinal lines, usually obscuring the surface, the apices acutish or blunt with the terminal cells slightly divergent, or clavate to bulbous; pappus 1–2 series of stiff scales, often with erose margins, united or reduced in some species, usually higher in disc than ray. Base chromosome number, x=4. (“for the Spanish nobleman Pedro Gutierrez” – fide Keck 1960, but the nature of the dedication not specified by Lagasca.)

      Type species: Gutierrezia linearifolia Lag. (= Gutierrezia sarothrae (Pursh) Britt. & Rusby) (see Lane 1982b).

      Gutierrezia comprises 16 species in North America, almost all of which occur in Mexico. Two of the three species not in Mexico are endemic to the western United States. An additional 11 species of Gutierrezia are endemic to southwestern South America (Solbrig 1966). The ditypic genus Amphiachyris also has been placed within Gutierrezia but is treated as distinct by Lane. The monotypic genus Thurovia from southeast Texas was included in Gutierrezia by Lane (1982), but recent molecular data support its status as a separate genus. Suh and Simpson (1991) found that Amphiachyris and Thurovia form the sister group to Gutierrezia. The taxonomic history of Gutierrezia has been intertwined with species of Xanthocephalum (Lane 1982a), which is superficially similar to Gutierrezia but more closely related to Grindelia and Isocoma of the Machaerantherinae.

      Plants of Gutierrezia are recognized by their taprooted habit, punctate leaves, small heads in a corymboid inflorescence, fimbriate receptacles, funnelform disc corollas, clavate-hairy cypselae, low-scaly or coronal pappus, and base chromosome number of x=4. They often occur in dense stands of relatively even height and cover large areas. Polyploidy is common but of little taxonomic significance; polyploids of different levels tend to be scattered through the range of a species, and populations often comprise mixtures of individuals of different euploid levels (Lane 1985).

 

references

 

Keck, D.D. 1960. Gutierrezia. In R.S. Ferris. Illustrated flora of the Pacific states 4:260–261.

Lane, M.A. 1982a. The generic limits of Xanthocephalum, Gutierrezia, Amphiachyris, Gymnosperma, Greenella, and Thurovia (Compositae: Astereae). Syst. Bot. 7:405–416. 1982.

Lane, M.A. 1982b. Neotypification of Gutierrezia linearifolia Lag. (Compositae: Astereae). Taxon 31:330–333.

Lane, M.A. 1985. Taxonomy of Gutierrezia (Compositae: Astereae) in North America. Syst. Bot. 10:7–28.

Nesom, G.L. and R. McVaugh. 2000. The identity of Grindelia angustifolia DC. ex Dunal (Asteraceae: Astereae). Novon in press.

Ruffin, J. 1974. A taxonomic evaluation of the genera Amphiachyris, Amphipappus, Greenella, Gutierrezia, Gymnosperma, Thurovia, and Xanthocephalum, (Compositae). Sida 5:301–333.

Ruffin, J. 1977. Palynological survey of the genera Amphiachyris, Amphipappus, Greenella, Gutierrezia, Gymnosperma, and Xanthocephalum (Compositae). Contr. Gray Herb. 207:117–131.

Solbrig, O.T. 1960a. Cytotaxonomic and evolutionary studies in the North American species of Gutierrezia. Contr. Gray Herb. 188:1–63.

Solbrig, O.T. 1960b. The status of the genera Amphiachyris, Amphipappus, Greenella, Gutierrezia, Gymnosperma, and Xanthocephalum (Compositae). Rhodora 62:43–54.

Solbrig, O.T. 1964. Infraspecific variation in the Gutierrezia sarothrae complex (Compositae–Astereae). Contr. Gray Herb. 193:67–115.

Solbrig, O.T. 1965. The California species of Gutierrezia. Madrono 18:75–84.

Solbrig, O.T. 1966. The South American species of Gutierrezia. Contr. Gray Herb. 197:3–42.

Solbrig, O.T. 1970. The phylogeny of Gutierrezia: An eclectic approach. Brittonia 22:217–229.

Suh, Y. and B.B. Simpson. 1991. Phylogenetic analysis of chloroplast DNA in North American Gutierrezia and related genera (Asteraceae: Astereae). Syst. Bot. 15:660–670.

 

43. GYMNOSPERMA Less., Syn. Comp. 194. 1832 [nom. nov. for Selloa Spreng.].

Selloa Spreng., Novi Provent. 36. 1819 [non Selloa Kunth in H.B.K. 1820, nom. conserv.].

 

Glabrous, heavily glutinous, taprooted shrubs 0.5–2 m tall. Leaves alternate, entire, linear to narrowly lanceolate, oblanceolate, or elliptic, mostly 2.5–5 cm long, relatively even in length up to the inflorescence, 1-nerved or with 3 parallel nerves in the wider blades, sessile, decurrent, often recurving or slightly falcate at the apex, punctate, margins minutely papillate-ciliolate. Heads sessile to subsessile in compact glomerules, these densely clustered and grouped in a terminal corymb; involucres turbinate-cylindric to elliptic-obovoid, 3–3.8 mm high; phyllaries in 2–4 graduate series, mostly completely whitish-indurate, achlorophyllous or the outer faintly green at the very apex; receptacles alveolate, glabrous. Ray florets pistillate, fertile, 4–9, the corollas 2–3 mm long, yellow. Disc florets 4–6, perfect, fertile or the ovaries sometimes sterile, the corollas orange-yellow, tubular-funnelform, the lobes lanceolate, reflexing-coiling; style branches with lanceolate to narrowly oblong-lanceolate, papillate collecting appendages. Cypselae columnar or fusiform to somewhat compressed, 1–1.4 mm long, strigillose with apically rounded-acute hairs, without evident nerves or ribs; pappus essentially absent or a minute corona with an erose or toothed margin, less than 0.1 mm high. Base chromosome number, x=4 or x=8. (Greek, gymnos, naked, sperma, seed, in reference to the epappose cypselae.)

      Type species: Gymnosperma glutinosum (Spreng.) Less.

      A monotypic genus and abundant element of the dry upland flora extending from the southwestern USA (Texas, New Mexico, and Arizona) through Mexico to Guatemala. Gymnosperma is recognized by its shrubby habit, glutinous stems, leaves, and heads, small heads in dense, terminal corymbs, few and inconspicuous rays, and epappose cypselae. It differs from Gutierrezia in its tendency to produce somewhat cylindrical heads, receptacles without hairs, ray florets without well-developed lamina, and a consistently more reduced pappus. Gymnosperma and Gutierrezia (plus Amphiachyris and Thurovia) apparently comprise a monophyletic group (Lane 1982; Suh & Simpson 1991; Nesom 1993), and in this interpretation, the chromosome number of Gymnosperma may be tetraploid, based on x=4. Gutierrezia, Amphiachyris, and Thurovia are closely related among themselves, and Gymnosperma has a similar habit, habitat, and geography and also shares with them small heads with few florets, similar phyllaries, a reduced pappus, and reduced chromosome number. Lane (1996) has recently suggested, in contrast, that the closest relative of Gymnosperma is the Caribbean genus Gundlachia (x=9), citing similarities in habit, capitulescence type, 3-nervate leaves, involucre shape, and phyllary, disc corolla, and style branch morphology.

 

references

 

Lane, M.A. 1982. Generic limits of Xanthocephalum, Gutierrezia, Amphiachyris, Gymnosperma, Greenella, and Thurovia (Compositae: Astereae). Syst. Bot. 7:405–416.

Lane, M.A. 1996. Taxonomy of Gundlachia (Compositae: Astereae). Brittonia 48:532–541.

Nesom, G.L., 1993. Taxonomic infrastructure of Solidago and Oligoneuron (Asteraceae: Astereae) and observations on their phylogenetic position. Phytologia 75:1–44.

Solbrig, O.T. 1961. Note on Gymnosperma glutinosum. Leafl. W. Bot. 9:147–150.

Suh, Y. and B.B. Simpson. 1991. Phylogenetic analysis of chloroplast DNA in North American Gutierrezia and related genera (Asteraceae: Astereae). Syst. Bot. 15:660–670.

 

44. HAZARDIA Greene, Pittonia 1:28. 1887.

 

Diplostephium subg. Aplostephium A. Gray, Proc. Amer. Acad. Arts 11:75. 1876.

Haplopappus sect. Hazardia (Greene) H.M. Hall, Carnegie Inst. Wash. 389:36. 1928.

 

Suffrutescent herbs (one species) or shrubs, erect, 2–25 m tall, usually highly branched. Leaves alternate, linear to ovate, obovate, or spatulate, 1.5–11 cm long, coriaceous, deciduous, resinous, entire or toothed, glabrous to densely tomentose, glandular-punctate in some, usually clasping or subclasping. Heads discoid or radiate, sessile or short-pedunculate in spicate, racemose, narrowly paniculate, or cymose inflorescences, rarely solitary; involucres cylindric to turbinate or campanulate, 5–20 mm high; phyllaries in 5–9 graduate series; receptacles shallowly foveolate. Ray florets absent or 3–25, pistillate, fertile or sterile, yellow or drying red-purple. Disc florets perfect, fertile or sterile, narrowly tubular, gradually ampliate from the middle; style branches with triangular collecting appendages. Cypselae fusiform to cuneate, 1–10 mm long, 4–5-nerved, subterete to compressed, glabrous to densely silky; pappus of numerous reddish-brown capillary bristles. Base chromosome numbers, x=4, 5, and 6. (“The name will signalize the eminent services rendered to Californian insular botany by Mr. Barclay Hazard, of Santa Barbara, the discoverer of Lyonothamnus asplenifolius, and our ready and generous helper in the matter of those fuller explorations of several of the Santa Barbara group of islands ...” – Greene 1887.)

      Type species: Hazardia cana (A. Gray) Greene.

      Hazardia is restricted to the Pacific coastal area from Oregon through California and southern Nevada to Baja California and Baja California Sur. Clark (1979) recognized three sections comprising 13 species, 10 of which occur in Mexico. All species have a chromosome number of 2n=10 except two; H. brickellioides (A. Gray) Clark (2n=12) and H. whitneyi (A. Gray) Greene (2n=8), both restricted to the USA. Species of Hazardia are particularly variable in vestiture, inflorescence, head shape and size, and biology of the heads (ray florets fertile or sterile, disc florets fertile or sterile).

      Clark maintained Hazardia as a distinct segregate of Haplopappus DC. but observed that South American species of Haplopappus probably are the closest relatives of Hazardia. Haplopappus in South America (ca. 70 species in 4 sections) has a range of variation similar to that of Hazardia (rays absent or present, fertile or sterile; base chromosome number, x=5). Haplopappus sect. Diplostephioides (Benth. & Hook.) Blake has been treated as the genus Llerasia Triana (Cuatrecasas 1970), recently placed in subtribe Hinterhuberinae (Nesom 1994). Haplopappus sects. Haplopappus and Gymnocoma Nutt. are closely related to each other, forming the core of the genus in its strict sense; sects. Polyphylla Hall and Xylolepis Hall, however, may be congeneric with Hazardia, based on morphological and chemical evidence (Clark 1979; Brown & Clark 1981; Brown & Clark 1982). Jackson (1979) and Grau (1976), more conservatively, have viewed Hazardia as congeneric with all of the South American Haplopappus species. Jackson would further include the species of Hall’s Haplopappus sect. Blepharodon (= Machaeranthera subg. Sideranthus (Nutt. ex Walpers) Hartman, sensu Hartman 1990) as congeners within Haplopappus. Molecular studies (Morgan 1997) suggest that sect. Sideranthus is removed from the Hazardia complex, but only a single South American species (Haplopappus glutinosus Cass., the generitype) has so far been included in the molecular analyses.

      Hazardia superficially resembles Isocoma and Hall (1928) considered them to be closely related. Hazardia differs from the latter, however, in its non-glomerate inflorescences, narrowly tubular, gradually ampliate disc corollas, lanceolate style appendages, and, for the most part, by its base chromosome number of x=5.

 

references

 

Brown, G.K. and W.D. Clark. 1981. Chromosome numbers in South American Haplopappus Cass. (Compositae). Amer. J. Bot. 68:1218–1221.

Brown, G.K. and W.D. Clark. 1982. Taxonomy of Haplopappus sect Gymnocoma (Compositae). Syst. Bot. 7:199–213.

Clark, W.D. 1979. The taxonomy of Hazardia (Compositae: Astereae). Madrono 26:105–127.

Cuatrecasas, J. 1970. Reinstatement of the genus Llerasia (Compositae). Biotropica 2:39–45.

Grau, J. 1976. Chromosomenzahlen von Sudamerikanischen Haplopappus-arten. Mitt. Bot. Mόnchen 12:403–410.

Greene, E.L. 1887. A new genus of Asteroid Compositae. Pittonia 1:28–30.

Hall, H.M. 1928. The genus Haplopappus – A phylogenetic study in the Compositae. The South American species of Haplopappus. Carnegie Inst. Washington Publ. No. 389:301–363.

Hall, H.M. 1928. The genus Haplopappus – A phylogenetic study in the Compositae. Section 14. Hazardia. Carnegie Inst. Washington Publ. No. 389:36, 243–257.

Hartman, R.L. 1990. A conspectus of Machaeranthera (Asteraceae: Astereae). Phytologia 68:439–465.

Jackson, R.C. 1979. Intersectional hybridization in Haplopappus: Blepharodon x Hazardia. Syst. Bot. 4:157–162.

Moran, R. 1969. Five new taxa of Haplopappus (Compositae) from Baja California, Mexico. Trans. San Diego Soc. Nat. Hist. 15:150–164.

Morgan, D.R. 1997. Reticulate evolution in Machaeranthera (Asteraceae). Syst. Bot. 22:599–615.

Nesom, G.L. 1994. Subtribal classification of the Astereae (Asteraceae). Phytologia 76:193–274.

 

45. HESPERODORIA Greene, Leafl. Bot. Observ. Crit. 1:173. 1906.

 

Haplopappus sect. Hesperodoria (Greene) H.M. Hall, Carnegie Inst. Wash. 389:35. 1928.

 

Perennial shrubs to subshrubs 3–10 dm tall, the stems glabrous to hirtellous, green to white-barked in age. Leaves linear-lanceolate to oblanceolate, ascending to spreading or deflexed, entire, 1–8 cm long, thick, with 3, raised, parallel veins, margins scabrous, the lamina glabrous to scabrous, punctate and resinous in H. salicinus (Blake) Nesom. Heads sessile to subsessile in terminal, 2–4-flowered glomerules or more numerous on pedicels 2–10 mm long, in cymose clusters, the aggregation loosely corymboid; involucres turbinate to cylindric-turbinate, 4–10 mm high; phyllaries in 5–6 subequal to graduate series, not in vertical ranks, oblong-lanceolate, chartaceous with greenish tips, with or without a glandular midline; receptacles flat, alveolate. Ray florets absent. Disc florets perfect, fertile, ca. 10–20, the corollas tubular-funnelform with triangular, deeply cut lobes; style branches with linear-lanceolate collecting appendages. Cypselae subterete, 1 or 4 mm long, 5–8-nerved, sparsely sericeous; pappus of 1–2 series of apically dilated, basally persistent, barbellate bristles. Base chromosome number, x=9 (as reported by Welsh et al. 1993). (Greek, hesperos, west, and “doria,” an early name for the goldenrod.)

      Type species: Hesperodoria scopulorum (M.E. Jones) Greene.

      A genus of two species of rocky habitats in Utah and Arizona: H. scopulorum in southern Utah and northern Arizona and H. salicinus in northern Arizona. These two species are similar in their subshrubby habit, 3-veined leaves, discoid heads in close clusters and in a loosely corymboid aggregate, and apically dilated pappus bristles. While the two species of Hesperodoria are very different between themselves, they are similar to the three species of Vanclevea and Petradoria, so much so that all five might be combined as a single genus (as noted by Nesom 1991). This observation has been carried further by Gary Baird (ms.), who provides a rationale for further combining all of these species into a broadened Chrysothamnus. Haplopappus hallii A. Gray, which was treated in Haplopappus sect. Hesperodoria by Hall (1928), has been segregated as the monotypic genus Columbiadoria (Nesom 1991).

 

references

 

Baird, G.I. Manuscript. A redefinition of Chrysothamnus (Asteraceae: Astereae).

Blake, S.F. 1935. Five new plants of the genus Aplopappus. Proc. Biol. Soc. Washington 48:169–174.

Greene, E.L. 1906. New Asteraceous genera. Leafl. Bot. Observ. Crit. 1:173–174.

Hall, H.M. 1928. The genus Haplopappus – A phylogenetic study in the Compositae. Section 12. Hesperodoria. Carnegie Inst. Washington Publ. No. 389:35, 218–222.

Nesom, G.L. 1991. Redefinition of Hesperodoria (Asteraceae: Astereae) and the segregation of Columbiadoria, a new monotypic genus from the western United States. Phytologia 71:244–251.

Welsh, S.L., N.D. Atwood, and S. Goodrich, and L.C. Higgins (eds.). 1993. A Utah flora (ed. 2, revised). Print Services, Brigham Young Univ., Provo, Utah.

 

46. HETEROTHECA Cass., Bull. Soc. Philom. (Paris) 1817:137. 1817.

 

Hectorea DC., Prodr. 5:95. 1836.

Chrysopsis subg. Phyllotheca Nutt., Trans. Amer. Philos. Soc. 2, 7:317. 1841.

Ammodia Nutt., Trans. Amer. Philos. Soc. 2, 7:321. 1841.

Chrysopsis subg. Ammodia (Nutt.) A. Gray, Proc. Amer. Acad. Arts 6:542. 1865.

 

Perennial or annual, taprooted or rhizomatous herbs (0.2–)2–4(–15) cm tall, often aromatic, the stems, leaves, and phyllaries often viscid with sessile or short-stipitate glands, also commonly hispid-pilose with stiff, non-glandular hairs. Leaves alternate, simple, ovate to lanceolate, 1–8 cm long, entire or with a few, shallow teeth, the basal often petiolate, the upper commonly clasping. Heads solitary or few or in open, corymboid clusters; involucres campanulate, 3–14 mm high; phyllaries lanceolate, rigid, in 4–8 graduate series; receptacles flat to convex, shallowly alveolate. Ray florets absent in two species (see below), otherwise pistillate, fertile, the lamina yellow to orange-yellow, coiling with maturity. Disc florets perfect, fertile, gradually and slightly ampliate upwards; style branches with linear-lanceolate collecting appendages. Cypselae 1–4 mm long, with 8–14 nerves or sometimes with a few thicker ribs, sparsely short-strigose to densely sericeous; in sect. Phyllotheca cylindrical to slightly compressed in outline; in sect. Heterotheca, the disc cypselae strongly compressed-obovate with 2 lateral ribs, the ray cypselae 3-angled and mostly glabrous; pappus of tawny to whitish barbellate bristles somewhat uneven in length, with a shorter, outer series of lanceolate scales or bristle-like squamellae, the pappus lacking or merely a short crown or a few much shorter bristles in ray cypselae of species of sect. Heterotheca. Base chromosome number, x=9. (Greek, heteros, different, theke, case or container, in reference to the dissimilar cypselae of ray and disc.)

      Type species: Heterotheca subaxillaris (Lam.) Britt. & Rusby.

      Heterotheca has often been treated to include Chrysopsis and Pityopsis, but recent studies have shown that these are three phyletically distinct groups (Semple et al. 1980; Nesom 1991). Heterotheca comprises about 25–30 species (28 as treated by Semple 1996) that occur in Mexico, the USA, and Canada. The plants are characterized as taprooted annual or perennial herbs, often coarsely hirsute or stiffly pilose to sericeous, commonly densely glandular, with golden-yellow-rayed heads in a loose, terminal, corymboid inflorescence; the pappus is composed of an inner series of long bristles and a short outer series. The genus is divided into three sections: sect. Heterotheca (ray cypselae epappose and glabrous or with reduced pubescence), sect. Phyllotheca (ray cypselae pappose and similar in pubescence to those of the disc), and sect. Ammodia (Nutt.) Harms (the rayless species H. oregona (Nutt.) Shinners, without a short, outer series of pappus bristles). One other species is rayless – H. brandegei (Rob. & Greenm.) Semple is derived from ancestors within sect. Phyllotheca (Nutt.) Harms (Semple et al. 1988). Relatively recent studies have considered the species of sect. Ammodia (Semple 1988), sect. Heterotheca (Wagenknecht 1960; Harms 1968; Nesom, 1990), and sect. Phyllotheca (Semple 1996; review by Nesom 1997). See related comments following Chrysopsis.

      Both of the larger sections of Heterotheca are discrete and include a number of closely related and often intergrading taxa. Hybridization and polyploidy are frequent among the species (Semple 1996) and apparently complicate the patterns of relationship and corresponding taxonomy. Varying concepts of the categories “subspecies” and “variety” also have contributed to differences in taxonomic applications and corresponding difficulties of interpretation (Nesom 1997).

 

references

 

Gray, A. 1865. Characters of some new plants of California and Nevada, chiefly from the collections of Professor William H. Brewer and Dr. Charles L. Anderson, with revisions of certain genera or groups. Proc. Amer. Acad. Arts 6:519–556.

Harms, V.L. 1965. Biosystematic studies in the Heterotheca subaxillaris complex (Compositae: Astereae). Trans. Kansas Acad. Sci. 68:244–257.

Harms, V.L. 1968. Nomenclatural changes and taxonomic notes on Heterotheca, including Chrysopsis, in Texas and adjacent states. Wrightia 4:8–20.

Nesom, G.L. 1990. Taxonomy of Heterotheca sect. Heterotheca (Asteraceae: Astereae) in Mexico, with comments on the taxa of the United States. Phytologia 69:282–294.

Nesom, G.L. 1991. A phylogenetic hypothesis for the goldenasters (Asteraceae: Astereae). Phytologia 71:136–151.

Nesom, G.L. 1997. Review: Revision of Heterotheca sect. Phyllotheca (Nutt.) Harms (Compositae: Astereae) by John C. Semple. Phytologia 83:7–21.

Semple, J.C. 1977. Cytotaxonomy of Chrysopsis and Heterotheca (Compositae–Astereae): a new interpretation of phylogeny. Canad. J. Bot. 55:2503–2513.

Semple, J.C. 1988. Heterotheca sect. Ammodia (Compositae: Astereae): A multivariate study of H. oregona and specimens of Brewer’s (golden)aster. Syst. Bot. 13:547–558.

Semple, J.C. 1996. A revision of Heterotheca sect. Phyllotheca (Nutt.) Harms (Compositae: Astereae). Univ. of Waterloo Biol. Ser. 37:i–iv, 1–164.

Semple, J.C., V. Blok, and P. Heiman. 1980. Morphological, anatomical, habit, and habitat differences among the goldenaster genera Chrysopsis, Heterotheca and Pityopsis (Compositae – Astereae). Canad. J. Bot. 58:164–171.

Shinners, L.H. 1951. The North Texas species of Heterotheca, including Chrysopsis (Compositae). Field & Lab. 19:66–71.

Wagenknecht, B.L. 1960. Revision of Heterotheca section Heterotheca (Compositae). Rhodora 62:61–76, 97–107.

 

47. IONACTIS Greene, Pittonia 3:245. 1897.

 

Diplopappus Cass. subg. Ianthe Torr. & A. Gray, Fl. N. Amer. 2:181. 1841.

Aster subg. Ianthe (Torr. & A. Gray) A. Gray, Synopt. Fl. 1(2):197. 1884.

 

Perennial herbs from a thick taproot, sometimes with woody caudex branches, 0.4–3(–7 in I. linariifolia) dm tall, rarely with creeping rhizomes, puberulent or usually glabrous, sometimes the leaf surfaces or margins scabrous, glandular in I. caelestis Nesom & Leary. Leaves all cauline or the basal persistent, congested on the stems, stiff and spreading at right angles or angled upward, linear to narrowly oblong or elliptic-lanceolate, 4–17 cm long, 1-nerved, mostly even in size and shape. Heads solitary or sometimes 2–3 or more and loosely corymboid on short simple branches originating near the top of the main stem; involucres broadly turbinate to campanulate, 4.5–13 mm high; phyllaries in 3–6 graduate series, linear-lanceolate, strongly keeled, even-textured, without a herbaceous apical patch. Ray florets pistillate, fertile, 8–21, violet to bluish or white, coiling. Disc florets perfect (ovaries sterile in I. caelestis), narrowly tubular; style branches with lanceolate collecting appendages. Cypselae narrowly obovate, 2–6 mm long, the ray (2–)3 nerved, the disc 2(–4) nerved, flattened, glandular in I. stenomeres (A. Gray) Greene and I. elegans (Soreng & Spellenb.) Nesom or eglandular, strigose to sericeous; pappus of 1–2 series of long, apically attenuate, barbellate bristles, with an outer series of much shorter bristles or narrow scales. Base chromosome number, x=9. (Greek, ion, violet, aktis, ray, referring to the colored ray florets.)

      Type species: Ionactis linariifolia (L.) Greene.

      A genus of five species – primarily of the western United States (with four species in that region), but the most widespread species (Ionactis linariifolia) is restricted to eastern North America. Ionactis has often been included within Aster but its morphological distinction has recently been reemphasized (Nesom & Leary 1992; Nesom 1992, 1994). Plants of Ionactis are distinctive in their woody caudex, narrow, stiff, evenly distributed leaves, solitary to few heads, flattened and slightly dimorphic cypselae, pappus of apically acute bristles with a short outer series, and base chromosome number of x=9.

      The hypothesized phyletic alliance of Ionactis with the Chrysopsidinae (Nesom 1991; Nesom & Leary 1992; and even much earlier, as Nuttall originally described one of the western species within Chrysopsis) emphasized their common production of carinate phyllaries without an apical patch, linear-lanceolate and hairy collecting appendages, oblique carpopodia, strongly shortened outer pappus series, and (in one species) glandular cauline vestiture. Plants of Ionactis, however, lack the large, straight-sided crystals in the disc corollas that are characteristic of the Chrysopsidinae, the rays are bluish to white rather than yellow, and the cypselae have fewer nerves than in most goldenasters. A more isolated position for the genus was hypothesized by Nesom (1994), this apparently confirmed by recent molecular studies (Xiang & Semple 1996).

 

references

 

Greene, E.L. 1897. Studies in the Compositae.–VI. Pittonia 3:243–246.

Nesom, G.L. and T.J. Leary. 1992. A new species of Ionactis (Asteraceae: Astereae) and an overview of the genus. Brittonia 44:247–252.

Nesom, G.L. 1991. A phylogenetic hypothesis for the goldenasters (Asteraceae: Astereae). Phytologia 71:136–151.

Nesom, G.L. 1992. Transfer of Chaetopappa elegans to Ionactis (Asteraceae: Astereae). Phytologia 73:416–424.

Nesom, G.L. 1994. Review of the taxonomy of Aster sensu lato (Asteraceae: Astereae), emphasizing the New World species. Phytologia 77:141–297.

Soreng, R.J. and R.W. Spellenberg. 1984. An unusual new Chaetopappa (Asteraceae – Astereae) from New Mexico. Syst. Bot. 9:1–5.

Xiang, C. and J.C. Semple. 1996. Molecular systematic study of Aster s. lat. and related genera (Asteraceae: Astereae) based on chloroplast DNA restriction site analyses and mainly North American taxa. In D.J.N. Hind and H.J. Beentje (eds.). Compositae: Systematics. Vol. 1, pp. 393–423. Proc. Interntl. Compositae Conf., Kew, 1994.

 

48. ISOCOMA Nutt., Trans. Amer. Philos. Soc. 2, 7:320. 1841.

 

Haplopappus sect. Isocoma (Nutt.) H.M. Hall, Carnegie Inst. Wash. 389:35. 1928.

Aplopappus sect. Aplodiscus DC., Prodr. 5:350. 1836.

 

Perennial subshrubs from a woody base, usually producing strictly erect, few-branched stems 1–25 dm tall, often glutinous, glabrous to villous, tomentose, or hispidulous. Leaves linear to oblanceolate or obovate, 0.5–5 cm long, papillate or glandular-punctate, usually glutinous, 1-nerved, entire to toothed or pinnatifid, the teeth or lobes usually spinulose-tipped. Heads discoid, sessile to subsessile in compact clusters, these in terminal corymbs, rarely solitary; involucres obconic to turbinate or campanulate, 3–9.5 mm high; phyllaries in (3–)4–6 graduate series; receptacle alveolate. Ray florets absent. Disc florets perfect, fertile, the corollas yellow with dark orange-resinous veins, abruptly ampliate, the tube with at least a few glandular hairs, the lobes deltate, erect, the tube elongating at maturity and elevating the corolla at anthesis, outer corollas prominently bent or leaning outward; style branches with narrowly triangular collecting appendages. Cypselae obpyramidal, 1.3–4(–5) mm long, terete or subterete, moderately to densely sericeous, 5–11-ribbed, the ribs sometimes very thick and resinous; pappus of numerous, thick, barbellate bristles in 2(–3) series of noticeably uneven length and thickness. Base chromosome number, x=6. (Greek, isos, equal, kome, hair of the head. “So called from its equal flowers.” – Nuttall 1841)

      Type species: Isocoma vernonioides Nutt. (= I. menziesii var. vernonioides (Nutt.) Nesom).

      A genus of 16 species endemic to Mexico and the southwestern USA; four species are restricted to the USA (Nesom 1991). Hall (1928) regarded the group as a section of Haplopappus, as it was maintained by Cronquist (1994). Isocoma is recognized by its shrubby habit, punctate or papillate, resinous leaves, compactly clustered discoid heads in terminal corymbs, goblet-shaped disc corollas, and base chromosome number of x=6. It is most closely related to other North American genera of Machaerantherinae with similar disc corollas and base chromosome number: Isocoma, Grindelia, Olivaea, Stephanodoria, Rayjacksonia, and Xanthocephalum. Naturally occurring hybrids in south-central Mexico have been observed between Isocoma veneta (Kunth) Greene and Xanthocephalum humile (Kunth) Benth. (Hartman & Lane 1991). Jackson (1966) and Jackson and Dimas (1981) considered the three species of the Haplopappus phyllocephalus DC. complex as part of Isocoma, but these have been segregated as the genus Rayjacksonia (Lane & Hartman 1996).

 

references

 

Cronquist, A. 1994. Intermountain flora. Vol. 5, Asterales. New York Botanical Garden, Bronx, N.Y.

Hall, H.M. 1928. The genus Haplopappus – A phylogenetic study in the Compositae. Section 13. Isocoma. Carnegie Inst. Washington Publ. No. 389:35, 222–243.

Hartman, R.L. & M.A. Lane. 1991. A natural intergeneric hybrid in the x=6 group of the Astereae (Asteraceae). Sida 14:321–329.

Jackson, R.C. 1966. Some intersectional hybrids and relationships in Haplopappus. Univ. of Kansas Sci. Bull. 46:475–485.

Jackson, R.C. and C.T. Dimas. 1981. Experimental evidence of systematic placement of the Haplopappus phyllocephalus complex (Compositae). Syst. Bot. 6:8–14.

Lane, M.A. and R.L. Hartman. 1996. Reclassification of North American Haplopappus (Compositae: Astereae) completed: Rayjacksonia gen. nov. Amer. J. Bot. 83:356–370.

Nesom, G.L. 1991. Taxonomy of Isocoma (Asteraceae: Astereae). Phytologia 70:69–114.

 

49. KALIMERIS (Cass.) Cass., Dict. Sci. Nat. 37:464. 1825.

 

Aster subg. Kalimeris Cass., Dict. Sci. Nat. 24:324. 1822.

Asteromoea Blume, Bijdr. 907. 1826.

Hisutsua DC., Prodr. 6:44. 1838.

Boltonia sect. Asteromoea (Blume) Benth. in Benth. & J.D. Hook., Gen. Pl. 2:269. 1873.

Aster sect. Asteromoea (Blume) Makino, Bot. Mag. (Tokyo) 12:60. 1898.

Martinia Vaniot, Bull. Acad. Int. Gιogr. Bot. 12:31. 1903.

 

Perennial herbs with erect stems 2–20 dm tall, from a fibrous-rooted rhizome or a taproot, stoloniferous in some. Basal rosettes and lower cauline leaves not persistent, the cauline evenly spaced, lanceolate to elliptic or oblanceolate, or linear, entire to coarsely toothed or lobed, 1–11(–15) cm long, gradually and slghtly reduced upwards, epetiolate, glabrous to strigose-hispid, sometimes glandular. Heads terminal, solitary on leafy peduncles, few to numerous and loosely corymboid on branches from the upper third of the main stem; involucres hemispheric to campanulate, 4–7 mm high; phyllaries in 3–4 graduate series, lanceolate to obovate, basally white-indurate, green-herbaceous above; receptacles convex to subconic, shallowly alveolate. Ray florets pistillate, fertile, 10–30, white to pinkish or bluish. Disc florets bisexual, symmetric, short-tubed at the base, abruptly ampliate into the limb, the lobes lanceolate; style branches with deltate to broadly lanceolate collecting appendages. Cypselae obovoid to broadly obovoid, 1.5–3.5 mm long, strongly flattened, with 2(–4) thickened nerves (the ray often with more nerves), strigose and glandular near the apex or merely glandular; pappus of 1 series of apically attenuate, barbellate bristles 0.1–1.5 mm long, sometimes reddish, essentially similar on ray and disc. Base chromosome number, x=9. (Greek, kalos, beautiful, meris, division or part, probably in reference to the aesthetic quality of the ray florets.)

      Type species: Kalimeris platycephala Cass. ex Nees, nom. illeg. (= Kalimeris incisa (Fisch.) DC.).

      A genus of eight species native to East Asia, ranging from the Amur Basin of northeastern China and adjacent Russia, Korea, and Japan, through central and southern China to northern Vietnam, Thailand, and Burma (Gu & Hoch 1997). Kalimeris indica (L.) Schultz-Bip. is naturalized in Hawaii (Nagata 1995): “Kauai: roadside near Limahuli Gardens, escape from cultivation (W.L. Wagner, pers. comm., 1995), 21 Dec 1983, Wagner, Mill, B. & C. Peterson, and Flynn 5162 (BISH); naturalized in lawn and secondary road near Haena, 28 May 1988, Nagata 3914 (BISH).”

      Kalimeris shares distinctive features with other genera of the “Kalimeris group” (Nesom 1994): leaves with coarsely toothed or lobed margins, heads on leafy branches in a loosely organized inflorescence, convex receptacles, short-tubed disc corollas, and reduced or caducous pappus. Gu and Hoch (1997) observed that the genus Heteropappus Less. and Aster sect. Ageratoides (Kitam.) Nesom are the groups most similar to Kalimeris. In a cpDNA study (Ito et al. 1994), Kalimeris, Heteropappus, and the sect. Ageratoides appear as discrete subgroups of a monophyletic clade. In the Old World sampling of Noyes and Rieseberg’s phylogenetic analysis (1999), Kalimeris and Aster appear as sister taxa. Generic boundaries among these putatively generic-level taxa, also including Miyamayomena Kitam. and Callistephus Cass., need to be examined in more detail and in a broader context of their relationships to other Asian groups of Aster s. lat. The long discussed possibility of a close relationship between the New World Boltonia and Old World Kalimeris (summary in Nesom 1994) is rejected by Gu and Hoch (1997).

      Natural hybrids have been documented between species of Kalimeris and Aster sect. Ageratoides (Inoue 1970; Tara 1972) and between Kalimeris and Heteropappus (Huziwara 1950; Inoue 1961; Tara 1973). Aster ovatus Fr. & Sav. (= A. ageratoides subsp. ovatus (Fr. & Sav.) Kitam.) is suggested to be a tetraploid amphiploid produced through hybridization between Aster ageratoides (DC.) Kuntze and a species of Kalimeris, perhaps K. pinnatifida (Maxim.) Kitam., based on morphological and karyotypic evidence (Tara 1977). Molecular phylogenetic study of a limited group of Asian species (Ito et al. 1994; Ito et al. 1995) indicates that A. ovatus has the chloroplast genome of Kalimeris. Aster ovatus forms natural backcross hybrids with species of Kalimeris (Inoue 1970; Tara 1972).

 

references

 

Gu, H. 1989. On chromosome numbers of Kalimeris (Astereae, Asteraceae) and some related taxa. Cathaya 1:1–16.

Gu, H. and M. Tara. 1990. On meiotic chromosomal disjunction pattern in some taxa of Kalimeris (Astereae, Asteraceae). Cathaya 2:11–20.

Gu, H., X.L. Zhao, L.J. Qu, L.X. Wen, and Z.L. Chen. 1994. Preliminary studies on the phylogeny of Kalimeris yomena subsp. yomena and two other taxa using RFLP analysis. Cathaya 6:27–34.

Gu, H. and P.C. Hoch. 1997. Systematics of Kalimeris (Asteraceae: Astereae). Ann. Missouri Bot. Gard. 84:762–814.

Huziwara, Y. 1950. Heterokalimeris maruyamae Kitamura. A new intergeneric hybrid of Kalimeris and Heteropappus. Jap. J. Genet. 25:25–26.

Inoue, S. 1961. Cytological and genetical studies on the interspecific and intergeneric hybrids in Heteropappus and Kalimeris. Kumamoto J. Sci. Ser. B. Sec. 2, 5:133–160.

Inoue, S. 1970. Cytological studies on the intergeneric natural hybrid between Aster and Kalimeris from Kyushu. I: Chromosome numbers and geographical distribution. Mem. Fac. General Ed., Kumamotu Univ. (Ser. Nat. Sci.) 5:47–52.

Inoue, S. 1970. Cytological studies on the intergeneric natural hybrid between Aster and Kalimeris from Kyushu. II: Natural hybrid between Aster ageratoides subsp. ovatus and Kalimeris yomena. Mem. Fac. General Ed., Kumamotu Univ. (Ser. Nat. Sci.) 5:53–76.

Ito, M., A. Soejima, and T. Nishino. 1994. Phylogeny and speciation of Asian Aster. Korean J. Pl. Taxon. 24:133–143.

Ito, M., A. Soejima, M. Hasebe, and K. Watanabe. 1995. A chloroplast–DNA phylogeny of Kalimeris and Aster, with reference to the generic circumscription. J. Pl. Research 108:93–96.

Nagata, K.M. 1995. New Hawaiian plant records. IV. Bishop Mus. Occ. Papers 42:10–13.

Nesom, G.L. 1994. Review of the taxonomy of Aster sensu lato (Asteraceae: Astereae), emphasizing the New World species. Phytologia 77:141–297.

Nishino, T. and T. Morita. 1994. 6-Phosphogluconate dehydrogenase (6PGD) gene duplication in Kalimeris (Asteraceae). Pl. Sp. Biol. 9:91-97.

Noyes, R.D. and L.H. Rieseberg. 1999. ITS sequence data support a single origin of North American Astereae (Asteraceae) and reflect deep geographic divisions in Aster s.l. Amer. J. Bot. 86:398–412.

Tara, M. 1972. Cytogenetic studies on natural intergeneric hybridization on Aster alliances. I. Aster ageratoides subsp. ovatus (2n=36) x Kalimeris incisa (2n=72). Bot. Mag. (Tokyo) 85:219–240.

Tara, M. 1973. Cytogenetic studies on natural intergeneric hybridization on Aster alliances. II. Heteropappus hispidus (2n=36) x Kalimeris incisa (2n=72). J. Sci. Hiroshima Univ., Ser. B, Div. 2, 14:107–140.

Tara, M. 1977. Cytogenetic studies on natural intergeneric hybridization on Aster alliances. IV. Experimental confirmation of the hybrid origin of Aster ageratoides subsp. ovatus. Bot. Mag. (Tokyo) 90:253–258.

 

50. KEYSSERIA Lauterbach, Repert. Spec. Nov. Regni Veg. 13:241. 1914.

 

Hecatactis F. Muell. ex Mattfeld, Bot. Jahrb. Syst. 62:407. 1929.

Myriactis subg. Hecatactis F. Muell., Trans. Royal Soc. Victoria 1, 2:13. 1889.

Keysseria sect. Hecatactis (F. Muell.) Mattf., Bot. Jahrb. 68:250. 1937.

 

Perennial, aromatic (as noted by collectors for several species), low herbs or short subshrubs 6–35 cm high, arising from a short, thick, fibrous-rooted rhizome-like base, or the stems becoming long-procumbent, lignescent, and rhizomiform with adventitious roots, the flowering branches erect or ascending, these usually with numerous, crowded, persistent, withered leaves or leaf bases. Leaves alternate, in a basal rosette or crowded and subrosulate at the top of the stem and branches, linear-terete to oblong or elliptic to lanceolate- or oblanceolate-spatulate, 1–7(–15) cm long, dilated and sheath-like at the base, petiolate or epetiolate, usually fleshy or coriaceous, glabrous to scabrous, tomentose, or silvery-villous, glandular or eglandular, the margins entire to minutely mucronulate or shallow dentate, often revolute. Heads terminal, solitary on long, scapiform peduncles with 1–6 leaflike bracts, usually radiate, often nodding; involucres campanulate or hemispheric, (3–)6–12 mm high; phyllaries in 2–4 series subequal in length, subfoliaceous, with a prominent midrib, usually glandular, the margins membranaceous, distally fringed; receptacles slightly convex, naked, alveolate. Ray florets pistillate, fertile, numerous, in 2–3 series, with a white to pinkish or purplish, short (1.5–8 mm long), linear, recurving, apically entire or lobed lamina, the heads thus short-radiate or disciform. Disc florets bisexual and fertile (Hawaii) or with sterile ovaries (Indonesia), the corollas infundibular, abruptly widening from the tube into the limb, with triangular to deltate lobes ca. 1/3–2/3 the length of the limb, the lobes 4 (Indonesia) or (3–)4(–5) (Hawaii); style branches without differentiated apical appendages. Fertile cypselae narrowly obovate to nearly elliptic, (1.5)2–3 mm long (without beak), laterally compressed with a pair of thickened lateral ribs, with a glandular neck or beak 0.5–1 mm long or merely a glandular apical collar, the faces glabrous or glabrate; sterile cypselae stalk-like; pappus absent. Base chromosome number, x=9. (For Christian Keysser, born 1877, who made the syntype collections of Keysseria papuana in northeastern New Guinea, 21 October 1912.)

      Type species: Keysseria papuana Lauterbach (= Keysseria radicans (F. Mueller) Mattf.), the sole species comprising the genus in the original description.

      A genus of 12 species, divided between Indonesia (nine species, including infraspecific taxa; Koster 1966) and Hawaii (three species; Mill 1990). All of the Indonesian species occur in New Guinea; K. radicans also is known from Celebes and K. gibbsiae (Merr.) Cabrera ex Steenis also occurs on Mt. Kinabalu in Borneo. The plants occur in wet and damp high elevation habitats – at forest edges or in alpine bogs or grasslands, (2400–)3150–4400 m (New Guinea) or 915–1980 m (Hawaii). Keysseria is briefly characterized as follows: perennial, aromatic, low herbs or short subshrubs from a thick rhizome, the primary leaves densely clustered or rosulate at the peduncle base, leaves linear to oblanceolate or spatulate, thick, often with revolute margins, basally dilated and sheathing, heads short-radiate to disciform, on scapiform peduncles, disc florets infundibular, 4(–5)-lobed, functionally staminate (Indonesia) or bisexual and fertile (Hawaii), and cypselae with a densely glandular collar, neck, or short beak. A chromosome number of 2n=54 has been reported for the Hawaiian K. helenae (Forbes & Lydgate) Cabrera (Carr 1985); the same number is indicated for K. maviensis (H. Mann) Cabrera (Mill 1990); chromosome numbers have not been reported for the Indonesian species.

      A brief overview of the genus, as Hecatactis, including four or five then-known Indonesian species, was provided by Mattfield (1929). He later (1937) updated the treatment, correcting the generic designation to Keysseria. Two species were segregated by Mattfield (1937) as Keysseria sect. Hecatactis, but this was not recognized by Koster (1966) as a natural division. The three Hawaiian species were excluded from Lagenifera and transferred to Keysseria by Cabrera (1966), as they have been recognized by some botanists (e.g., St. John 1971; Carr 1985). Mill (1990), in contrast, maintained them in a broadly conceived Lagenifera, indicating that Keysseria was to be regarded as a synonym, without other specific comments; her descriptions of the morphology and geographic range at generic level suggest that Lagenifera, Keysseria and Myriactis may have been included in her concept of Lagenifera. Swenson and Bremer (1994) also explicitly regarded Keysseria as a synonym of Lagenifera.

      The monotypic genus Piora Koster (Koster 1966) is similar to Keysseria in its alpine habitat (in New Guinea), thick-leaved, shrubby habit, aromatic herbage, and other morphological details but differs in the rather evenly arranged (vs. rosulate) leaves, anthers completely lacking an apical appendage, and apically truncate cypselae. Keysseria and Piora may be most closely related to Myriactis (which see) within the subtribe Lageniferinae.

      The Hawaiian plants of Keysseria are generally similar to the Indonesian ones in habitat, habitat, and morphology but differ as follows: disc florets with fertile ovaries, ray corollas usually deeply and asymmetrically 2–4 lobed at the apex, disc corollas sometimes 5-lobed, cypselae essentially beakless (or short-beaked in one species) but with a sparsely glandular cartilaginous rim at the apex. Mill (1990) noted that the three Hawaiian species apparently are “from one founder;” they have been formally recognized as Keysseria sect. Sandwicactis Nesom (Nesom in press).

      Along with Keysseria, the genera Tetramolopium in Hawaii and Myriactis in Central America have congeners in Indonesia, presumably the area of origin of the outlying Hawaiian and American population systems. In all three genera, plants of the Asian (and presumably ancestral) species have functionally staminate disc florets (sterile ovaries), while the Hawaiian and Central American derivatives (presumably by dispersal) have fully bisexual disc florets (fertile ovaries). In contrast, South American species of Lagenifera Cass. (also presumably derivative by dispersal from Australasian populations) have retained the functionally staminate disc florets characteristic of the Australasian plants and appanretly invariable within the genus.

 

references

 

Cabrera, A.L. 1966. The genus Lagenophora (Compositae). Blumea 14:285–307.

Carr, G.D. 1985. Additional chromosome numbers of Hawaiian flowering plants. Pacific Sci. 39:302–304.

Koster, J.T. 1966. Keysseria. The Compositae of New Guinea I. Nova Guinea, Bot., 24:597–608.

Lauterbach, C. 1914. Neue Bergpflanzen aus Kaiser-Wilhelms-Land. Repert. Spec. Nov. Regni Veg. 13:239–250.

Mattfield, J. 1929. Die Compositen von Papuasien. Bot. Jahrb. Syst. 62:386–451.

Mattfield, J. 1937. Einige neue oder bemerkenswerte Compositen aus Neuguinea. Bot. Jahrb. Syst. 68:248–268.

Mill, S.W. 1990. Lagenifera. Pp. 329–331 in W.L. Wagner, D.R. Herbst, and S.H. Sohmer. Manual of the Flowering Plants of Hawai’i. Vol. 1. Univ. of Hawaii Press, Honolulu.

Nesom, G.L. 1994. Pytinicarpa (Asteraceae: Astereae), a new genus from New Caledonia. Phytologia 76:136–142.

Nesom, G.L. In press. Taxonomic notes on the genus Keysseria (Asteraceae: Astereae). Phytologia.

St. John, H. 1971. Endemic plants of Kipahulu Valley, Maui, Hawaiian Islands. Pacific Sci. 25:39–79.

Smith, A.C. and G.D. Carr. 1991. Asteraceae. In A.C. Smith. Fl. Vitiensis Nova 5:254–320.

Swenson, U. and K. Bremer. 1994. The genus Lagenocypsela (Asteraceae, Asteraceae) in New Guinea. Austr. Syst. Bot. 7:265–273.

 

51. LAENNECIA Cass., Dict. Sci. Nat. 25:91. 1822.

 

Conyza sect. Laennecia (Cass.) Cuatr., Webbia 24:206. 1969 (non Phytologia 9:1. 1963).

 

Taprooted annuals, biennials, or short-lived perennials (fibrous-rooted in L. confusa (Cronq.) Nesom), 1–7(–10) dm tall, the leaves, stems, and phyllaries white-tomentose or cottony, coarsely hairy in 2 species, glandular with sessile, translucent, orange-yellow, resin glands, eglandular in 4 species. Leaves alternate, lanceolate or oblanceolate to oblong or elliptic, 0.5–3 cm long, toothed to pinnately lobed, rarely entire, epetiolate, clasping or non-clasping. Heads in a spicate or racemose to loosely paniculate or corymboid inflorescence; involucres turbinate, 2.5–7 mm high; phyllaries in 2–5 subequal to graduate series; receptacles without pales. Pistillate florets numerous in several series, fertile, white, filiform-tubular, eligulate and apically fimbriate, much shorter than the style, or some species with a lamina 0.2–2.5 mm long. Disc florets perfect, fertile, the corollas cream to yellowish, narrowly tubular-funnelform, ampliate near the origin of the lobes, the lobes triangular-lanceolate; style branches with deltate to narrowly triangular collecting appendages. Cypselae narrowly oblanceolate-elliptic to obovate in outline, 0.7–3 mm long, compressed, with sessile or short-stipitate resin glands on the faces, rarely eglandular; pappus of 1–2 series of slender, barbellate, often easily caducous bristles, sometimes elongating at maturity past the disc corollas and involucres, with or without an outer series of much shorter setae, bristles, or scales. Base chromosome number, x=9. (Greek, lenos, woolly hair, in reference to the vestiture; the epithet of the generitype also alludes to its woolly vestiture.)

      Type species: Laennecia gnaphalioides (Kunth) Cass.

      Laennecia comprises 17 Mexican and South American species that occur primarily in montane habitats or at least in temperate highlands (rather than tropical habitats). Wide disjunctions occur between population systems of several Laennecia species (between North/Central America and South America and between west/northwest Mexico and south-central Mexico/Central America). The species often have been regarded as Conyza, based on their possession of eligulate or short-ligulate pistillate florets in numerous series (Nesom 1990). The species of Laennecia, however, are generally distinguished from Conyza by phyllaries with a single, greenish (vs. orange-resinous) midvein, light-veined (vs. orange-veined) disc corollas with lanceolate (vs. deltate) lobes, presence of achenial glands, and accrescent pappus bristles. Most of the Laennecia species also have herbage with a resinous-glandular, woolly-tomentose vestiture. The genus has been divided into two sections: sect. Laennecia has white-tomentose vestiture, short-ligulate ray florets, and cypselae with large, persistent glands; sect. Sophiifolium Nesom has hirsute-pilose vestiture, eligulate ray florets, and cypselae with small, more deciduous glands. The closest relatives of Laennecia are postulated to be genera of South America (Nesom 1994) and Australasia.

 

references

 

Cuatrecasas, J. 1969. Conyza. Prima flora Colombiana. 3. Compositae – Astereae. Webbia 24:198–228.

Nesom, G.L. 1990. Taxonomy of the genus Laennecia (Asteraceae: Astereae). Phytologia 68:205–228.

Nesom, G.L. 1994. Subtribal classification of the Astereae (Asteraceae). Phytologia 76:193–274.

Zardini, E.M. 1981. Contribuciσnes para una monografνa del gιnero Conyza Less. II. Rehabilitacion del gιnero Laennecia Cass. Darwiniana 23:159–169.

 

52. LAESTADIA Kunth ex Less., Syn. Comp. 203. 1832.

 

Intricately branched herbs, procumbent or with a few erect stems up to 15 cm high, with glandular-punctate, resinous stems and leaves, sometimes hirtellous as well. Leaves linear, oblong to oblanceolate, or spatulate, 3.5–16 mm long, entire, 1-nerved, sessile, subclasping or not, alternate to subopposite, crowded and nearly imbricate in some species. Heads discoid, solitary, terminal or axillary, on peduncles leafy, naked, or bracteolate, 1–4 cm long; involucres hemispheric, 2.2–4 mm high; phyllaries in 2–4 subequal series; receptacles flat to slightly convex, without chaff. Outer florets in ca. 2–4 series, 1–4 times as numerous than the inner, pistillate, fertile, corollas actinomorphic with 4–5 deeply cut, triangular, spreading-recurved lobes, sessile-glandular in some; style branches with stigmatic lines from base to apex, without sweeping hairs. Disc florets relatively few (15–25), functionally staminate with sterile ovaries, the corollas abruptly ampliate above a very short, narrow tube, the lobes triangular, cut nearly to the base of the limb, white to purple; style branches with ovate-acute collecting appendages, without stigmatic lines. Fertile cypselae oblong to obovoid, 1.5–2.5 mm long, nearly terete, 6–10-nerved, glandular; pappus absent, the cypsela apex with a thickened ring of glands, or if short-beaked, the beak glandular. (Derivation unknown.)

      Type species: Laestadia pinifolia Kunth ex Less.

      A genus of six species, four at high altititudes in the Andes from Venezuela and Colombia to Peru and Bolivia, one on the island of Santo Domingo (L. domingensis Urb.), and one in the paramos of Costa Rica (L. costaricensis Blake). Recognized by their high-elevation habitats, mostly prostrate habit, glandular vestiture, discoid heads with both inner and outer florets regular and goblet-shaped with deeply cut lobes, the inner functionally staminate, the outer perfect, and fertile (outer) cypselae with an apical ring of glands or glandular beak. The genus has been placed in the Hinterhuberinae, where its relationships apparently are with other herbaceous Andean genera of low habit (Nesom 1993, 1994).

 

references

 

Aristeguieta, L. 1964. Laestadia. Flora de Venezuela 10(2):247–249.

Cuatrecasas, J. 1969. Laestadia. Prima flora Colombiana. 3. Compositae – Astereae. Webbia 24:9–15.

Nesom, G.L. 1993. Floscaldasia (Asteraceae: Astereae): first record from Ecuador and comments on its classification. Phytologia 75:366–368.

Nesom, G.L. 1994. Subtribal classification of the Astereae (Asteraceae). Phytologia 76:193–274.

 

53. LESSINGIA Cham., Linnaea 4:203. 1829.

 

Annual, taprooted herbs, erect to decumbent, 1–80 cm high, the stems relatively simple to divaricately branched, glabrous to densely and closely white-tomentose, usually with large, tack-shaped glands, also sessile-glandular. Leaves basal and cauline, the basal petiolate and in rosettes, basal and lower cauline oblanceolate to obovate or spatulate, 0.3–5 cm long, entire to serrate or pinnately lobed, sometimes spinulose-tipped, the upper smaller and sessile. Heads discoid, ca. 5–50-flowered, in glomerulate, spiciform, or paniculiform inflorescences; involucres cylindric to narrowly turbinate or campanulate, 4–10 mm high; phyllaries green-tipped, sometimes mucronate, in 3–7 imbricate series. Florets all bisexual, fertile, the corollas yellow, lavender, rose, or white, 5-lobed, the inner tubular-funnelform, the outer series irregular, bilateral, the 5 lobes of each becoming short, ray-like extensions; style branches with truncate to subulate collecting appendages. Cypselae turbinate, 2–3 mm long, silky-villous; pappus of numerous bristles of unequal length, reddish-brown, distinct or united into clusters or reduced to 5 paleaceous awns. Base chromosome number, x=5. (For the Lessing family, including Christian Friedrich Lessing, 1810–1862, a student of the Asteraceae.)

      Type species: Lessingia germanorum Cham.

      A genus of about 7–10 species and numerous varieties, recognized by their annual duration, capitate-glandular and tomentose vestiture, and small heads with all florets bisexual, the outer bilateral, and green-tipped phyllaries. The heads are variable in size, shape, and arrangement. All species occur in California; some have outlying populations in adjacent Nevada, Arizona, and Baja California. Lane (1993a, 1993b) recently proposed a broadening of the genus with the inclusion of Corethrogyne and Benitoa, but Nesom (1994) noted that each of these three generic-level taxa is monophyletic and as morphologically distinct as other Astereaean genera. Lessingia, Corethrogyne, and Benitoa are members of the subtribe Machaerantherinae (see Benitoa for comments). Molecular evidence of Markos and Baldwin (submitted) corroborates the earlier observation (Nesom 1994) that Lessingia and Corethrogyne are sister taxa but indicates that Benitoa is more closely related to Hazardia. Markos and Baldwin follow Lane in consolidating Lessingia and Corethrogyne, while Saroyan et al. (submitted) maintain Corethrogyne as a distinct genus. The two genera can be separated by the following contrast.

 

1. Perennial; heads solitary or 2–5(–20+) in loosely corymbiform, or rarely spicate, associations; ray florets present, pistillate but sterile; disc corollas regular................................................................................................................................................................................... Corethrogyne

1. Annual; heads usually 5–50+ in glomerulate, spiciform, or paniculiform associations; ray florets absent; corollas of the inner disc florets regular, those of the outer series bilateral, with lobes becoming short, ray-like extensions.............................................................................. Lessingia

 

references

 

Howell, J.T. 1929. A systematic study of the genus Lessingia Cham. Univ. of California Publ. Bot. 16:1–44.

Lane, M.L. 1993a. New combinations in Californian Lessingia (Compositae: Astereae). Novon 3:213–214.

Lane, M.L. 1993b. Lessingia. Pp. 304–306 in J.C. Hickman (ed.). The Jepson manual: Higher plants of California. Univ. of California Press, Berkeley.

Markos, S. and B.G. Baldwin. Submitted. Higher-level relationships and major lineages of Lessingia (Compositae, Astereae) based on nuclear rDNA internal and external transcribed spacer (ITS and ETS) sequences. Syst. Bot.

Nesom, G.L. 1994. Subtribal classification of the Astereae (Asteraceae). Phytologia 76:193–274.

Saroyan, J.P., D.R. Parnell, and J.L. Strother. Submitted. Revision of Corethrogyne (Compositae: Astereae). Madrono.

Spence, W.L. 1963. A biosystematic study of the genus Lessingia Cham. (Compositae). Ph.D. diss., Univ. of California, Berkeley.

 

54. MACHAERANTHERA Nees, Gen. Sp. Aster. 224. 1832.

 

Aster sect. Machaeranthera (Nees) Benth. & J.D. Hook., Gen. Pl. 2:272. 1873.

Haplopappus sect. Blepharodon DC., Prodr. 5:346. 1836.

Sideranthus Nutt. ex Nees in Wied-Neuw., Reise Nord-America 2:440. 1840.

Dieteria Nutt., Trans. Amer. Philos. Soc. 2, 7:300. 1841.

Machaeranthera subg. Dieteria (Nutt.) Greene, Pittonia 3:59. 1896.

Dieteria sect. Sideranthus (Nutt. ex Nees) Nutt. ex Walp., Repert. Bot. Syst. 2:587. 1843.

Dieteria subg. Sideranthus (Nutt. ex Nees) Nutt., J. Acad. Nat. Sci. Philadelphia 2, 1:177. 1848.

Eriocarpum Nutt., Trans. Amer. Philos. Soc. 2, 7:320. 1841.

Haplopappus sect. Havardii R. Jackson, Univ. of Kansas Sci. Bull. 46:479. 1966.

Hesperastrum A. Gray, Proc. Amer. Acad. Arts 6:539. 1865.

Aster sect. Hesperastrum (A. Gray) A. Gray, Syn. Fl. N. Amer. 1(2):174. 1884.

Aster subg. Hesperastrum (A. Gray) A. Gray, Proc. Amer. Acad. Arts 16:97. 1881.

Chrysopsis subg. Pappochroma Nutt., J. Acad. Nat. Sci. Philad. 7:34. 1834.

Dieteria subg. Pappochroma (Nutt.) Nutt., Trans. Amer. Philos. Soc. 2, 7:302. 1841.

Dieteria sect. Pappochroma (Nutt.) Walpers, Rep. Bot. Syst. 2:587. 1843.

 

Annual to perennial herbs or subshrubs, 0.5–10 dm tall, usually taprooted, rhizomatous in a few, the stems, leaves, and phyllaries stipitate-glandular to eglandular, variably pubescence with eglandular trichomes. Leaves alternate, linear to oblong, lanceolate, oblanceolate, or spatulate, 1–6 cm long, the margins spinulose-serrate or spinulose-pinnatifid, less commonly entire but then the apex usually spinulose, sessile to subclasping. Heads radiate or eradiate, mostly solitary on short or long peduncles; involucres turbinate to hemispheric, 5–8 mm high; phyllaries in 2–10 strongly graduate to nearly equal series, erect to spreading or reflexing, the lower part whitish-indurated, the upper herbaceous or with a green apical patch; receptacles smooth to strongly alveolate. Ray florets when present pistillate, fertile, ligulate, the corollas white to blue, lavender, or yellow. Disc florets numerous, hermaphroditic, fertile, yellow, cylindric to gradually ampliate, with triangular-deltate, erect lobes; collecting appendages of the style branches mostly triangular-attenuate. Cypselae turbinate to cylindric-turbinate or fusiform-oblong, 2–4 mm long, terete to 3-sided or flattened, strigose to densely sericeous; pappus of 1–3 series of numerous, thick bristles or bristle-like awns, usually markedly uneven in length and thickness, basally flattened in most, sometimes reduced or lacking on the ray cypselae. Base chromosome numbers, x=4, 5. (Greek, machaira, dagger, antheros, anther, alluding to the dagger-like appearance of the thick, apical appendages of the anthers.)

      Type species: Machaeranthera tanacetifolia (Kunth) Nees.

      Machaeranthera as currently considered is a variable group of about 30 species, 24 or 25 of them in Mexico (Hartman 1990), the remainder in the USA. The genus is recognized by its taprooted habit, spinulose-tipped leaves, solitary or few-headed inflorescence, gradually widening disc corollas, relatively small, turbinate cypselae with multiseriate pappus of numerous, thick, bristles, and base chromosome numbers of x=4 and 5. Morphological studies (Hartman 1990) and molecular studies (Morgan & Simpson 1992; Morgan 1997) suggest that the group may be polyphyletic, but evidence so far is equivocal and apparently contradictory for some subgroups. Sects. Machaeranthera, Hesperastrum A. Gray, and Arida Hartman appear to be coherent as a group; sect. Blepharodon (DC.) Hartman and subg. Sideranthus (Nutt. ex Nees) Hartman are closely related to each other. The interpolation of other morphologically well-defined and generally accepted genera of Machaerantherinae (Xanthisma, Xylorhiza, Oonopsis, Pyrrocoma) at varying places within the phyletic topology of Machaeranthera (according to molecular data) complicates the interpretation. “Comparisons of cpDNA, ITS, and morphological evidence suggest that evolution within the Machaeranthera group has been complex, with multiple occurrences of reticulate evolution as well as substantial variation in morphological divergence, and possibly hybrid speciation” (Morgan 1997, p. 611).

      Machaeranthera sect Psilactis (A. Gray) Turner & Horne is treated here at generic rank (as Psilactis) following Morgan (1993).

 

references

 

Cronquist, A. and D.D. Keck. 1957. A reconstitution of the genus Machaeranthera. Brittonia 9:231–239.

Hall, H.M. 1928. The genus Haplopappus – A phylogenetic study in the Compositae. Section 2. Blepharodon. Carnegie Inst. Washington Publ. No. 389:33, 53–84.

Hartman, R.L. 1990. A conspectus of Machaeranthera (Asteraceae: Astereae). Phytologia 68:439–465.

Morgan, D.R. 1993. A molecular systematic study and taxonomic revision of Psilactis (Asteraceae: Astereae). Syst. Bot. 18:290–308.

Morgan, D.R. 1997. Reticulate evolution in Machaeranthera (Asteraceae). Syst. Bot. 22:599–615.

Morgan, D.R. and B.B. Simpson. 1992. A systematic study of Machaeranthera (Asteraceae) and related groups using restriction site analysis of chloroplast DNA. Syst. Bot. 17:511–531.

Turner, B.L. 1987. Taxonomic study of Machaeranthera, sections Machaeranthera and Hesperastrum (Asteraceae). Phytologia 62:207–266.

 

55. MONOPTILON Torr. & A. Gray ex Gray, Boston J. Nat. Hist. 5:106. 1845.

 

Eremiastrum A. Gray, Mem. Amer. Acad. Arts 2, 5:321. 1854.

 

Small, taprooted annuals with prostrate to decumbent branches radiating from the base, 1–5 cm high, the stems, leaves, and phyllaries hispid-hirsute with long, white hairs and minutely glandular. Leaves alternate, small, oblong to oblanceolate-spatulate, 4–20 mm long. Heads solitary; involucres campanulate, 4–6 mm high, usually immediately subtended and surrounded by the uppermost leaves; phyllaries linear-lanceolate, purple-tipped, in 1(–2) equal-length series; receptacles without chaff, flat. Ray florets pistillate, fertile, 12–21, white or tinged with rose or purple, strongly coiling. Disc corollas yellow with prominent orange veins, 3–4 mm long, narrowly tubular-funnelform; style branches with obtuse to truncate collecting appendages. Cypselae obovate, 1.5–2 mm long, compressed, 2-nerved, sparsely strigose; pappus of a short-toothed cup and a single apically plumose bristle (M. bellidiforme) or 1–12 barbellate bristles alternating with shorter, laciniate paleae. Base chromosome number, x=8. (Greek, monos, one, ptilon, soft feather, referring to the pappus of M. bellidiforme. “The generic name is expressive of its most striking peculiarity, that of a pappus composed of a solitary plumose bristle!” – Gray 1845)

      Type species: Monoptilon bellidiforme Torr. & A. Gray ex Gray.

      A genus of two species of desert habitats in the southwestern USA and adjacent Mexico. Both are decumbent to prostrate, hispid annuals with campanulate heads and white, conspicuously coiling rays, obovate, compressed cypselae, and chromosome number of 2n=16. The genus was brought from one to two species by Hall (1907), who added Monoptilon (Eremiastrum) bellioides (A. Gray) Hall. Each of the two species has a distinct pappus morphology but they are otherwise very similar. Monoptilon was placed by Nesom (1994) as the sister genus of Chaetopappa.

 

references

 

Ferris, R.S. 1960. Monoptilon. Illustrated flora of the Pacific states 4:304–305.

Gray, A. 1845. Characters of some new genera and species of plants of the natural order Compositae, from the Rocky Mountains and Upper California. Boston J. Nat. Hist. 5:104–111.

Hall, H.M. 1907. Monoptilon, in Compositae of southern California. Univ. of California Publ. Bot. 3:74-75.

Keil, D.J. 1993. Monoptilon. P. 319 in J.C. Hickman (ed.). The Jepson manual: Higher plants of California. Univ. of California Press, Berkeley.

Nesom, G.L. 1994. Subtribal classification of the Astereae (Asteraceae). Phytologia 76:193–274.

 

56. MYRIACTIS Less., Linnaea 6:127. 1831.

 

Botryadenia Fisch. & Mey., Index Sem. Horti Petrop. 2:30. 1835.

Lagenifera [as Lagenophora] sect. Pseudomyriactis Cabrera, Blumea 14:303. 1966.

 

Perennial herbs, from a short, erect or oblique, thickened (1.5–4 mm thick) rhizome with somewhat fleshy fibrous roots, the stems 1 to ca. 4 per plant, decumbent or ascending to erect, simple or with few–many branches above the middle, (3.5–)10–50 cm high or long, subglabrous to sparsely or moderately hirsute-villous with septate hairs. Leaves cauline, distributed throughout or mostly restricted to the lower half of the stems, obovate to oblanceolate to ovate or orbicular, 1–11 cm long, the lower often petiolate-spatulate, clasping to subclasping, crenate-dentate to shallowly lobed, pinnatisect, or lyratiform, sometimes with slightly revolute margins. Heads radiate, 1–many, on peduncles 1–6 cm long; involucres cupulate to hemispheric, 4–6 mm high; phyllaries oblong-lanceolate, in 2–4 subequal to graduate series, herbaceous, with a conspicuous, basally carinate midrib. Ray florets in 2-5(–10) series, ca. 10–45 or more, fertile or sterile, the lamina (0.5–)1–4 mm long, greenish-white to white or pinkish, purpling in age. Disc florets bisexual and fully fertile or functionally staminate (see below); corollas 1.5-2.5 mm long, goblet-shaped, abruptly opening into a broad limb, the lobes 4 or 5 (see below), lanceolate, spreading to spreading-reflexing; style branches with ovate-deltate collecting appendages ca. as long as the stigmatic lines. Cypselae obovate to oblanceolate, 2–4 mm long, strongly flattened, with 2 thickened margins, the faces shiny, eglandular, the apex constricted into a densely sessile-glandular beak 0.1–0.4 mm long, or the disc cypselae erostrate; pappus absent. Base chromosome number, x=9. (Greek, myrios, innumerable, and aktis, ray, particularly in reference to the ca. 10-seriate rays of the type species.)

      Lectotype species (Grierson 1980, p. 151): Myriactis nepalensis Less.

      Myriactis, broadly considered, comprises 22 species divided between the Old World and New World. In the region considered here, six Central American species constitute a natural group tentatively maintained within Myriactis. Of these species, one is endemic to Guatemala, two to Costa Rica, and one to Panama; one species occurs in Costa Rica and Panama, and one is known from Costa Rica as well as Venezuela. Cuatrecasas (1982) noted that the group perhaps radiated both northward and southward from its center of diversity in Costa Rica. The plants are briefly characterized as follows: perennial herbs from a short, thick rhizome, with lax, erect-ascending to decumbent, unbranched stems and solitary heads, rarely with 1–4 short branches above the middle; leaves thin-herbaceous, flat-margined, sometimes subclasping but not basally dilated or sheathing, the basal often persistent but the cauline continuing unreduced in size halfway to nearly completely up the stem; disc florets with fertile ovaries, the corollas 5-lobed and infundibular, abruptly opening into a broad limb.

      Within subtribe Lageniferinae, plants of Myriactis are distinguished by their leafy stems and glandular but erostrate or merely short-beaked cypselae (Nesom in press). The short, short-tubed disc corollas of Myriactis are infundibular (goblet-shaped, abruptly widening from the tube into the limb) and similar in this respect to those in Keysseria (which see) and its close monotypic relative Piora Koster, compared to disc corollas in other genera of Lageniferinae (including Lagenifera), which gradually open into the limb.

      Although these American species appear to move to Myriactis Less. in Cabrera’s key (1966) to Lagenifera Cass. and related genera, he maintained them within Lagenifera as sect. Pseudomyriactis, apparently because of their tendency for solitary heads (compared to Myriactis s. str.) and short-beaked cypselae. Blake (1939, pp. 314–317) observed that Lagenifera panamensis is most similar to the Hawaiian Keysseria (Lagenifera) maviensis (Mann) Cabrera among all of the Lagenifera species (s. lat.) available to him for study. Beaman and DeJong (1965, p. 40) confirmed the similarity observed by Blake between these two species and noted that “the Central and northern South American species [of Lagenifera s. lat.] seem to have more characters in common among themselves than with other members of the genus.” Drury (1974, p. 366) left open “the possibility that this singular section [Lagenifera sect. Pseudomyriactis] is anomalous in Lagenifera.” Based on cypsela morphology, Velez (1981) concluded that Lagenifera andina Badillo is more similar to Myriactis than to Lagenifera. Five of these six species were transferred from Lagenifera to Myriactis by Cuatrecasas (1986), who observed their dissimilarity to Lagenifera (which has functionally staminate disc florets, scapose stems, and long-beaked cypselae) and greater similarity to the Asian species of Myriactis.

      The remaining 16 species of Myriactis are native to the Old World. Five species similar in habit to the American ones are restricted to southeast Asia, where they occur in from Japan southward through Taiwan, eastern China (Yunnan), Vietnam, Thailand, the Malay Archipelago, Philippines, Borneo, Celebes, Moluccas, and New Guinea. Myriactis s. str. includes about 11 species distributed from the Caucasas through the Himalayas to southeast China, Indo-China, and Indonesia. These three nodes of variation characterizing Myriactis (in the present sense) are contrasted in the key below.

 

1. Annual or biennial, from shallow fibrous roots; stems stiffly erect, 10–50 cm tall, with numerous, leafy, lateral branches, each bearing a terminal, long-pedunculate head, the inflorescence subpaniculate; disc florets with fertile ovaries, the corollas 4-, 4–5-, or 5-lobed. Myriactis s. str.

1. Perennial, from a thickened rhizome; stems lax, erect-ascending to decumbent, 3.5–25 cm tall, unbranched and the inflorescence of a solitary head, or sometimes with 1–4 short branches above the middle, each bearing a head; disc florets with fertile or sterile ovaries, the corollas 5-lobed or 4-lobed. (b)

2. Disc florets with fertile ovaries, the corollas 5-lobed................................................................... “American Pseudomyriactis”

2. Disc florets with sterile ovaries, the corollas 4-lobed........................................................................ “Asian Pseudomyriactis”

 

The American species apparently comprise a discrete group, but the boundary between “Asian Pseudomyriactis” and “Myriactis s. str.” is not clear. In particular, the habit of Myriactis humilis Merr., of Taiwan and the Philippines, generally is low and the plants grow from a short rhizome (“Pseudomyriactis”), but the flowering stems are long pedunculate and vary from unbranched to numerous-branched with a loose grouping of heads and the disc florets fully fertile (Myriactis s. str.). A taxonomic overview of Myriactis and study of species delimitations in all putative subgroups are much needed.

 

references

 

Beaman, J.H. and D.C.D. De Jong. 1965. A new species of Lagenophora (Compositae) from Guatemala. Rhodora 67:36–41.

Blake, S.F. 1939. Compositae. In R.E. Woodson and R.J. Seibert. Contributions toward a Flora of Panama III. Ann. Missouri Bot. Gard. 26:265–324.

Cabrera, A.L. 1966. The genus Lagenophora (Compositae). Blumea 14:285–307.

Cuatrecasas, J. 1982. Miscellaneous notes on Neotropical flora, XV. New taxa in the Astereae. Phytologia 52:166–177.

Cuatrecasas, J. 1986. Un genero nuevo de Astereae, Compositae, de Colombia. Anales Jard. Bot. Madrid 42:415–426.

Drury, D.G. 1974. A broadly based taxonomy of Lagenifera section Lagenifera and Solenogyne (Compositae–Astereae), with an account of their species in New Zealand. New Zealand J. Bot. 12:365–396.

Grierson, A.J.C. 1980. Astereae. Rev. Handbook Fl. Ceylon 1:111–278.

Nesom, G.L. 1999 [2000]. Taxonomic notes on Keysseria and Pytinicarpa (Asteraceae: Astereae, Lageniferinae). Phytologia, in press.

Velez, M.C. 1981. Carpologische Untersuchungen an amerikanischen Astereae (Compositae). Mitt. Bot. Staats. Mόnchen 17:1–170.

 

57. NEJA D. Don in Sweet, Hort. Brit. (ed. 2) 299. 1830

 

Neja sect. Podoneja DC., Prodr. 5:325. 1836.

Neja sect. Monogyria DC., Prodr. 5:325. 1836.

 

Perennial herbs (2–)10–30 cm high, usually from a thick taproot bearing thick caudex branches. Leaves mostly basally disposed, filiform to linear-oblanceolate, sometimes slightly fleshy, 1–6 cm long, crinkly pilose with long, spreading cilia. Heads solitary on long scapes or few-bracteate stems; involucres broadly turbinate to hemispheric, 6–10 mm high; phyllaries narrowly triangular and sharply acute, keeled, with 1–3 longitudinal veins accompanied by orange resin ducts, in 2–4 graduate series; receptacles nearly flat to slightly convex, foveolate, epaleate. Ray florets pistillate, fertile, 1-seriate, yellow or white, if white tending to dry yellowish. Disc florets perfect, fertile, yellow, tubular and regular, the lobes deltate, erect; style branches with deltate collecting appendages. Cypselae fusiform-cylindric, 2–2.5 mm long, with 7–10 prominently raised, orange-resinous nerves, densely strigose between the nerves; pappus of 1–3 series of barbellate bristles, with a distinct outer series barely differentiated or of short, setaceous bristles to broad scales. Base chromosome number unknown, predicted x=9. (Derivation of name unknown.)

      Type species: Neja gracilis D. Don (= Neja filiformis [Spreng.] Nees).

      A genus of about six species mostly of southeastern Brazil and adjacent Uruguay, Paraguay, and Argentina. Neja marginata (Griseb.) Nesom is endemic to western Cuba (Nesom 1993). Plants of Neja are recognized as perennial herbs from a thick taproot and caudex of long, ascending, woody branches, filiform to linear-oblanceolate leaves concentrated at the base of the plant, solitary heads on long, leafless peduncles, yellow rays or white rays drying yellowish, fusiform-cylindric cypselae with numerous, raised, orange-resinous nerves, and pappus of bristles usually with a short, outer series.

      Species of the genus Hysterionica Willd. were noted to be divided without intermediacy into the “jasonioides group” (Hysterionica s. str., seven species) and the “pinifolia group” (Nesom 1993). The latter were later resegregated as the earlier described genus Neja (Nesom 1994a). Apart from much older literature, descriptions of Neja species are found mostly in taxonomic treatments of Hysterionica (Cabrera 1946; Ariza Espinar 1980), the broader definition adopted by both authors without comment, following Bentham’s much earlier relegation of Neja to synonymy. Compared to Neja, plants of Hysterionica s. str. are annual or perennial, more slenderly taprooted with a simple caudex, have leaves obovate and evenly distributed on the stems, and produce flattened, 2-nerved cypselae. The glossy leaves with parallel veins and the terete, multinerved cypselae of Neja were hypothesized to indicate a closer relationship to another austro-Brasilian genus, Apopyros Nesom, than to Hysterionica (Nesom 1994a, 1994b) but recent ITS data on the Conyzinae from Noyes (2000) suggest that Neja and Hysterionica are indeed sister taxa.

 

references

 

Alain, H. [A. Liogier]. 1962. Compositae. Flora de Cuba 5:175–313.

Ariza Espinar, L. 1980. Las especies centroargentinas de Hysterionica (Compositae). Darwiniana 22:537–549.

Cabrera, A.L. 1946. El genero Hysterionica en el Uruguay y en la Republica Argentina. Notas Mus. La Plata 11(Bot. 53):349–358.

De Candolle, A.P. 1836. Neja. Prodr. 5:325–326.

Nesom, G.L. 1993. A Cuban endemic: Hysterionica marginata (Asteraceae: Astereae) rather than Aster grisebachii. Phytologia 75:163–165.

Nesom, G.L. 1994a. Separation of Neja (Asteraceae: Astereae) from Hysterionica. Phytologia 76:168–175.

Nesom, G.L. 1994b. Apopyros (Asteraceae: Astereae), a new genus from southern Brazil, Argentina, and Paraguay. Phytologia 76:176–184.

Noyes, R.D. 2000. Biogeographical and evolutionary insights on Erigeron and allies (Asteraceae) from ITS sequence data. Pl. Syst. Evol. 220:93–114.

 

58. OCLEMENA Greene, Leafl. Bot. Observ. Crit. 1:4. 1903.

 

Galatella sect. Calianthus Nutt., Trans. Amer. Philos. Soc. 2, 7:303. 1841.

Aster subg. Orthomeris Torr. & A. Gray, Fl. N. Amer. 2:156. 1841.

Aster sect. Orthomeris (Torr. & A. Gray) Benth. in Benth. & Hook., Gen. Pl. 2:273. 1873.

Aster sect. Nemorali House, New York State Mus. Bull. 254:710. 1924.

 

Perennial herbs, the stems usually simple until the inflorescence, 2–9 dm tall, densely and closely puberulent with hairs with colored cross-walls. Leaves with sessile-glandular surfaces, oblong, elliptic, or oblanceolate, 2–12 cm long, sessile or short-petiolate, entire or serrate, all cauline, increasing in size upwards toward midstem, the lowermost reduced to scale-like bracts. Heads on long, naked peduncles arching-nodding in bud, in a loosely corymboid inflorescence; involucres broadly turbinate, 5–10 mm high; phyllaries in 3–4 graduated series, linear-lanceolate with acute apices, evenly thin-herbaceous, slightly keeled, without a green apical patch; receptacles without chaff. Rays florets pistillate, fertile, white to pinkish-purple (in O. nemoralis (Ait.) Greene). Disc florets perfect, fertile, the corollas pink or reddish at anthesis, with deltate, erect lobes; style branches with narrowly lanceolate, distally papillate collecting appendages. Cypselae fusiform to narrowly obovate or oblong in outline, 2.8–3.5 mm long, 4–8-nerved, plump though often evidently flattened and with the two lateral nerves thicker than the others, the surfaces densely sessile-glandular; pappus of 2–3 subequal series of barbellate bristles, with an outer series of much shorter setae in O. acuminata and O. reticulata. Base chromosome number, x=9. (Derivation of name unknown.)

      Type species: Oclemena acuminata (Michx.) Greene.

      An eastern North American group of three species recently resegregated from Aster (Nesom 1994), distinctive from possibly related genera in its glandular leaves, arching-nodding peduncles of buds and young heads, lanceolate, evenly herbaceous, and keeled phyllaries, and densely glandular cypselae. Oclemena blakei (Porter) Nesom is a fertile, recurrent hybrid between O. acuminata and O. nemoralis. Evidence from cpDNA studies (Xiang & Semple 1996) indicates that Oclemena (Aster) reticulata (Pursh) Nesom belongs with Doellingeria, as it was treated by Semple et al. (1991). As observed in detail by Nesom (1994), however, and summarized in a formal couplet contrasting Doellingeria and Oclemena (1994, p. 178), morphological features place the species within Oclemena, where it is maintained here, at least until the apparent inconsistency between morphological and molecular characters is resolved.

 

references

 

Brouillet, L. and J.-P. Simon. 1981. An ecogeographical analysis of the distribution of Aster acuminatus Michx. and A. nemoralis Aiton (Asteraceae: Astereae). Rhodora 83:521–550.

Greene, E.L. 1903. Further segregates from Aster. Leafl. Bot. Observ. Crit. 1:4–7.

Hill, L.M. 1976. Morphological and cytological evidence for introgression in Aster acuminatus Michx. in the Southern Appalachians. Castanea 41:148–155.

Hill, L.M. and O.M. Rogers. 1970. Chromosome numbers of Aster blakei and A. nemoralis. Rhodora 72:437–438.

Hill, L.M. and O.M. Rogers. 1973. Chemical, cytological and genetic evidence for the hybrid origin of Aster blakei (Porter) House. Rhodora 75:1–25.

Nesom, G.L. 1994. Review of the taxonomy of Aster sensu lato (Asteraceae: Astereae), emphasizing the New World species. Phytologia 77:141–297.

Semple, J.C., J.G. Chmielewski, and C. Leeder. 1991. A multivariate morphometric study and revision of Aster subg. Doellingeria sect. Triplopappus (Compositae: Astereae): The Aster umbellatus complex. Canad. J. Bot. 69:256–276.

Xiang, C. and J.C. Semple. 1996. Molecular systematic study of Aster s. lat. and related genera (Asteraceae: Astereae) based on chloroplast DNA restriction site analyses and mainly North American taxa. In D.J.N. Hind and H.J. Beentje (eds.). Compositae: Systematics. Vol. 1, pp. 393–423. Proc. Interntl. Compositae Conf., Kew, 1994.

 

59. OLIGONEURON Small, Fl. Southeast. U.S. [ed. 1] 1188. 1903.

 

Solidago sect. Corymbosae Torr. & A. Gray, Fl. N. Amer. 2:208. 1842.

Solidago subg. Oligoneuron (Small) House, New York State Mus. Bull. 254:693. 1924.

 

Erect perennial herbs from short rhizomes, stems usually simple until the inflorescence, (1–)3–15 dm tall. Leaves narrowly lanceolate or broadly elliptic, 6–24 cm long, parallel- or net-veined, entire or rarely serrulate, often evidently glandular-punctate, the basal commonly persistent. Heads in a distinctly flat-topped, corymboid inflorescence; involucres turbinate to campanulate or hemispheric, 4–8 mm high; phyllaries in 3–6 series, broadly oblong to oblong-obovate, each usually with 3–7 (or more) translucent, parallel veins from base to apex; receptacle without chaff. Ray florets pistillate, fertile, yellow (white in one species), conspicuous but relatively short. Disc florets perfect, fertile; style branches with triangular-lanceolate to linear collecting appendages. Cypselae oblong-fusiform, (0.7–)1–2.3 mm long, terete to slightly compressed, glabrous, with 5–7(10–20) thin, whitish to brownish, longitudinal nerves beneath the surface; pappus (1–)2 series of equal to subequal, apically attenuate or clavate barbellate bristles. Base chromosome number, x=9. (Greek, oligos, few, neuron, nerve, apparently referring to the parallel veins of the phyllaries)

      Lectotype species (Nesom 1993): Oligoneuron rigidum (L.) Small.

      An eastern North American group of six species and various named hybrids, often included as a section or subgenus within Solidago. Recent cpDNA data (Zhang 1996) indicate that Oligoneuron is monophyletic and that it may occupy a phyletically basal position within Solidago, leaving the assignment of rank open to subjectivity. Semple et al. (1999) treated it within Solidago.

            A morphological analysis (Nesom 1993) indicated two possible positions of phyletic origin for Solidago s. str. within subtribe Solidagininae: “position 1” – a relatively primitive origin (apart from Oligoneuron) near Columbiadoria, Oreochrysum, and Tonestus and “position 2” – a sister relationship with Oligoneuron, closer to Euthamia, Bigelowia, and other genera that also have a strongly flat-topped inflorescence and punctate leaves similar to Oligoneuron.

      Oligoneuron is distinguished from Solidago s. str. by its tendency for punctate leaves, strongly flat-topped inflorescence, broad phyllaries with parallel venation, and cypselae with subsurface nerves. Recurrent hybridization occurs in various combinations among species of Oligoneuron, which apparently are genetically isolated from species of Solidago s. str. Interspecific hybrids in many combinations and across sectional lines, however, are formed within the latter.

 

references

 

Brouillet, L. and J.C. Semple. 1981. A propos du status taxonomique de Solidago ptarmicoides. Canad. J. Bot. 59:17–21.

Heard, S.B. and J.C. Semple. 1988. The Solidago rigida complex (Compositae: Astereae): A multivariate morphometric analysis and chromosome numbers. Canad. J. Bot. 66:1800–1807.

Nesom, G.L. 1993. Taxonomic infrastructure of Solidago and Oligoneuron (Asteraceae: Astereae) and observations on their phylogenetic position. Phytologia 75:1–44.

Semple, J.C., G.S. Ringius, and J.J. Zhang. 1999. The goldenrods of Ontario: Solidago L. and Euthamia Nutt. (ed. 3). Univ. of Waterloo Biol. Ser. 39:1–90.

Zhang, J.J. 1996. A molecular biosystematic study on North American Solidago and related genera (Asteraceae: Astereae) based on chloroplast DNA RFLP analysis. Ph.D. diss., Univ. of Waterloo, Waterloo, Ontario, Canada.

 

60. OLIVAEA Schultz-Bip. ex Benth. in Hook., Ic. Pl. t. 1103. 1872.

 

Oligonema S. Wats., Proc. Amer. Acad. Arts 26:138. 1891 [non Rost. 1875].

Golionema S. Wats., Bot. Gaz. 16:267. 1891 [nom. nov. based on Oligonema S. Wats.].

 

Erect aquatic annuals from a taproot, immersed for the most part, simple and glabrous below, 4–12 dm tall, cymosely branched and stipitate-glandular above, the stems soft and swollen at maturity; peduncles, involucre copiously capitate-glandular. Leaves alternate, sessile, clasping to subclasping, glandular when young, otherwise glabrous or minutely ciliolate, usually linear to lanceolate and entire above, 3–10 cm long, the submerged ones lobed but quickly deciduous. Heads solitary on leafy peduncles, few-20; involucres hemispheric, 4–7 or 10–15 mm high; phyllaries in ca. 3 series, fleshy, basally fused, herbaceous above, chartaceous below; receptacle flat to convex, naked or alveolate. Ray florets pistillate, fertile, 25–50, uniseriate, yellow, coiling upon maturity. Disc florets hermaphroditic, fertile, the corollas tubular; style branches with narrowly triangular to subulate appendages. Cypselae squarish or oblanceolate, flattened, 2–3.6 mm long, 2–3-winged or 2-nerved, glabrous, shiny, smooth; pappus of 2–12 caducous, unequal, retrorsely barbellate bristles. Base chromosome number, x=6. (For Guadalajara, Mexico, scholar of pharmacology and botany Prof. Leonardo Oliva, 1805–1873.)

      Type species: Olivaea tricuspis Schultz-Bip. ex Benth.

      A genus of two species endemic to southwestern Mexico. Olivaea is closely related to Grindelia, from which it differs in its aquatic habitat, hollow stems, leaves without resinous punctations, united phyllary bases that are chartaceous rather than indurated, winged cypselae, and pappus of retrorsely barbellate bristles. The production of winged cypselae in the South American G. chiloensis (Cornel.) Cabrera and close relatives (see Bartoli & Tortosa 1994, 1999) lessens the distinctiveness of Olivaea in this respect and suggests that these two Mexican species may have arisen from within Grindelia. The production of winged achenes in these South American species may represent more of a tendency than strict inheritance, because the immediate ancestor of G. cabrerae var. alatocarpa Ariza apparently has non-winged achenes (Bartolia & Tortosa 1999). In any case, these South American species need to be included in the consideration of the phyletic position and taxonomic rank of Olivaea.

 

references

 

Bartoli, A. and R.D. Tortosa. 1994. Tres nueva especies de Grindelia (Asteraceae), afines a G. chiloensis (Corn.) Cabr. Kurtziana 23:131–150.

Bartoli, A. and R.D. Tortosa. 1999. Revisiσn de las especies sudamericanas de Grindelia (Asteraceae: Astereae). Kurtziana 27:327–359.

De Jong, D.C.D. and J.H. Beaman. 1963. The genus Olivaea (Compositae–Astereae). Brittonia 15:86–92.

McVaugh, R. 1984. Olivaea, in Flora Novo-Galiciana 12:643–644.

 

61. OONOPSIS (Nutt.) Greene, Pittonia 3:45. 1896.

 

Stenotus sect. Oonopsis Nutt., Trans. Amer. Philos. Soc. 2, 7:335. 1841.

Haplopappus sect. Oonoopsis (Nutt.) H.M. Hall, Carnegie Inst. Wash. Publ. 389:34. 1928.

 

Perennial herbs 0.5–3 dm tall, with a deep taproot and somewhat woody, branched caudex, glabrous or sparsely tomentose. Leaves alternate, linear to narrowly oblanceolate or lanceolate, 2–10 cm long, entire, densely arranged and continuing little reduced to immediately below the heads. Heads solitary or up to 12 in loose corymbs, or nearly glomerate, subtended by upper cauline leaves little reduced in size; involucres hemispheric to campanulate or cylindric-turbinate, 7–22 mm high; phyllaries in 3–6 imbricate series, abruptly acuminate to cuspidate, herbaceous or the inner chartaceous, appearing to grade from the upper cauline leaves; receptacles without chaff. Ray florets absent or 6–25, pistillate, fertile, yellow, with lamina 5–15 mm long. Disc florets perfect, fertile, funnelform, short-tubed; style branches with triangular collecting appendages. Cypselae prismatic or narrowly turbinate, 5–7 mm long, strigose to glabrous; pappus of comparatively few, brownish, rigid, barbellate bristles of unequal length. Base chromosome number, x=5. (Greek, oφn, egg, opsis, likeness, for a perceived egg-like appearance of the heads. Nuttall’s 1841 description of sect. Oonopsis noted “involucrum small, ovate” but did not elaborate on the derivation of the name.)

      Type species: Oonopsis multicaulis (Nutt.) Greene.

      A genus of four or five species early recognized by Greene as a natural group, characterized by a relatively low habit, thick taproots, even-sized cauline leaves continuing up the stems and subtending the heads, abruptly acuminate, foliaceous outer phyllaries, and yellow rays. The genus primarily occurs in Colorado, Montana, and Wyoming, with outlying populations in Kansas, Nebraska, and South Dakota. All taxa apparently are selenium primary indicator plants (Rosenfeld & Beath 1964). Molecular data suggest that Oonopsis arose evolutionarily from within the genus Machaeranthera (Morgan & Simpson 1992; Morgan 1997), as the latter is currently interpreted.

 

references

 

Bricker, J.S. and G.K. Brown. 1998. A molecular phylogeny for Oonopsis (Asteraceae). Amer. J. Bot. [abstract] 85(6):170.

Brown, G.K. 1993. Systematics of Oonopsis (Asteraceae). Amer. J. Bot. [abstract] 80(6):133–134.

Brown, G.K. and W.D. Clark. 1989. Flavonoids of Haplopappus section Oonopsis. Amer. J. Bot. [abstract] 76(6):190.

Evans, T.M. and G.K. Brown. 1991. Chloroplast DNA variation in Haplopappus section Oonopsis (Asteraceae). Amer. J. Bot. [abstract] 78(6):185.

Greene, E.L. 1896. Studies in the Compositae. – III. Pittonia 3:43–63.

Hall, H.M. 1928. The genus Haplopappus – A phylogenetic study in the Compositae. Section 4. Oonopsis. Carnegie Inst. Washington, Publ. 389:34, 86–95.

Hughes, J.F. and G.K. Brown. 1994. Putative hybridization between two varieties of Goldenweed (Oonopsis foliosa: Asteraceae). Amer. J. Bot. [abstract] 81(6):162–163.

Morgan, D.R. 1997. Reticulate evolution in Machaeranthera (Asteraceae). Syst. Bot. 22:599–615.

Morgan, D.R. and B.B. Simpson. 1992. A systematic study of Machaeranthera (Asteraceae) and related groups using restriction site analysis of chloroplast DNA. Syst. Bot. 17:511–531.

Nuttall, T. 1841. Descriptions of new species and genera of plants in the natural order of the Compositae, collected ... during the years 1834 and 1835. Trans. Amer. Philos. Soc. 2, 7:283–453.

Rosenfeld, I. and O.A. Beath. 1964. Selenium, geobotany, biochemistry, toxicity, and nutrition. Academic Press, New York.

Schulz, K.A. and R.B. Shaw. 1992. Status of Haplopappus fremontii ssp. monocephalus (A. Nelson) Hall (Asteraceae) in Colorado. Prairie Nat. 24:143–148.

 

62. OREOCHRYSUM Rydb., Bull. Torrey Bot. Club 33:152. 1906.

 

Haplopappus sect. Oreochrysum (Rydb.) H.M. Hall, Carnegie Inst. Wash. 389:35. 1928.

Solidago subg. Oreochrysum (Rydb.) Semple, Univ. of Waterloo Biol. Ser. 39:23. 1999.

 

Herbaceous perennials 1.5–6(–10) dm tall, producing long, slender, scale-leaved rhizomes, these thickening somewhat and lignifying with age. Stems often purple on the lower part, the whole length minutely puberulous or hirtellous with a mixture of stipitate-glandular and non-glandular hairs. Leaves viscid with minute, short-stipitate or sessile resin glands, the basal and lower cauline persistent, spatulate-oblanceolate with a distinct petiolar region, (3–)6–15 cm long, the midcauline and upper elliptic to broadly ovate-lanceolate or oblanceolate, clasping or subclasping, less commonly non-clasping, relatively unreduced up to the inflorescence. Heads in distinctly flat-topped and tightly clustered corymboid cymes; involucres campanulate to hemispheric, 10–11 mm high; phyllaries thin-textured, green-tipped and spreading-reflexing at the apices, with a single, slender, non-resinous midvein, rarely with a lateral pair, usually strongly graduated in length, the outer ovate, sometimes grading into the upper leaves, the inner broadly lanceolate-oblong, 8–11 mm long. Ray florets pistillate, fertile, 12–20, the yellow lamina 6–10 mm long and prominently exceeding the phyllaries. Disc florets perfect, fertile, the corollas narrowly tubular-funnelform, 7–9 mm long, with triangular, spreading lobes; style branches with linear collecting appendages. Cypselae fusiform, plump but distinctly compressed, 3–4.5 mm long, glabrous, with 12–16 raised, whitish nerves; pappus of numerous, equal-length barbellate bristles in 2(–3) series. Base chromosome number, x=9. (Greek, oreios, of mountains, chrysos, gold.)

      Type species: Oreochrysum parryi (A. Gray) Rydb.

      A monotypic genus of western North America, from Wyoming, Colorado, and Utah to New Mexico and Arizona. It was collected by C.G. Pringle from a single locality in Chihuahua, Mexico, but apparently is now extinct there. This species has often been treated as Solidago parryi (A. Gray) Greene (beginning with Greene 1894), and Zhang’s cpDNA data (1996) place it as the sister group to Solidago s. lat. (including Oligoneuron). Semple et al. (1999), following Zhang’s data, has formally placed Oreochrysum at subgeneric rank within Solidago. Oreochrysum, however, is separated from Solidago on the basis of its stipitate-glandular vestiture, large heads in a strongly corymboid inflorescence, herbaceous phyllaries, narrow disc corollas with relatively short lobes, linear-lanceolate collecting appendages, large, multinerved cypselae, and multiseriate pappus, and it has no apparent close relatives within Solidago. Hall (1928) maintained the species within Haplopappus, where it was originally described by Gray (1862) as “Aplopappus (Pyrrocoma) parryi.” Gray’s further assessment perhaps prefigured the apparently isolated position of the species – he noted (p. 239) that it had “somewhat the aspect of a Sericocarpus, especially of S. oregonensis.” Rydberg (1906, p. 152) observed that Oreochrysum “is just as much out of place [in Solidago] as among its old associations, i.e., the present genus Stenotus.” Molecular data of Morgan (1990) and Lane et al. (1996) place Oreochrysum as more closely related to Hesperodoria, Tonestus, Stenotus, Petradoria, and other western U.S.A. genera than to Solidago.

 

references

 

Gray, A. 1862. Enumeration of the plants [collected by C.C. Parry in 1861 in the Rocky Mountains]. Amer. J. Sci. ser. 2, 33:237–243.

Greene, E.L. 1894. Observations on the Compositae. – IV. Erythea 2:53–60.

Hall, H.M. 1928. The genus Haplopappus – A phylogenetic study in the Compositae. Section 10. Oreochrysum. Carnegie Inst. Washington Publ. No. 389:35, 208–212.

Morgan, D.R. 1990. A systematic study of Machaeranthera (Asteraceae) and related groups using restriction site analysis of chloroplast DNA and a taxonomic revision of Machaeranthera section Psilactis. Ph.D. diss., Univ. of Texas, Austin.

Nesom, G.L. 1993. Taxonomic infrastructure of Solidago and Oligoneuron (Asteraceae: Astereae) and comments on their phylogenetic position. Phytologia 75:1–44.

Rydberg, P.A. 1906. Studies on the Rocky Mountain flora – XVI. Bull. Torrey Bot. Club 33:137–161.

Semple, J.C., G.S. Ringius, and J.J. Zhang. 1999. The goldenrods of Ontario: Solidago L. and Euthamia Nutt. (ed. 3). Univ. of Waterloo Biol. Ser. 39:1–90.

Zhang, J.J. 1996. A molecular biosystematic study on North American Solidago and related genera (Asteraceae: Astereae) based on chloroplast DNA RFLP analysis. Ph.D. diss., Univ. of Waterloo, Waterloo, Ontario, Canada.

 

63. OREOSTEMMA Greene, Pittonia 4:224. 1900 [nom. nov., based on Oreastrum Greene].

 

Oreastrum Greene, Pittonia 3:146. 1896 [non Oriastrum Poeppig 1843].

 

Herbaceous, taprooted (sometimes thick-rhizomatous) perennials, sometimes with a branching caudex, the stems essentially scapose, 2–70 cm high, 3–35 cm long, eglandular or stipitate-glandular, the upper stems and phyllaries commonly finely and loosely tomentose. Leaves mostly in a basal rosette, linear to narrowly oblanceolate, entire, 3-nerved, the cauline alternate, reduced. Heads solitary; involucres broadly turbinate, 5–12 mm high; phyllaries in 3–4 subequal series, linear to linear-elliptic or oblanceolate, nearly completely foliaceous, or the basal margins sometimes indurate, sometimes with evident stomates, often with a low keel; receptacle without chaff. Ray florets pistillate, fertile, white. Disc florets perfect, fertile, the corollas tubular with deltate, erect lobes, remaining yellowish at maturity; style branches with linear-lanceolate collecting appendages. Cypselae narrowly cylindric, 4–5 mm long, with 5–10 raised nerves, glabrous or sparsely short-strigose; pappus of 1 series of barbellate bristles, sometimes with a few short bristles or setae in a second series. Base chromosome number, x=9. (Greek oreo, mountain, stemma, crown.)

      Type species: Oreostemma alpigenum (Torr. & A. Gray) Greene.

      A sharply delimited group of three species of western North America, recognized by a basal rosette of narrow, 3-nerved leaves, solitary heads on scapose stems, turbinate involucres with 2–3 subequal series of evenly herbaceous phyllaries, white rays, linear-lanceolate collecting appendages commonly reaching 2 mm long, and cylindric cypselae. The species consistently have been treated within Aster. After an initial hypothesis (Nesom 1993) of close relationship with the primarily South America genus Oritrophium, Nesom (1994) placed Oreostemma as closely related to Eurybia, emphasizing the multi-nerved, cylindric cypselae. Molecular data of Xiang and Semple (1996) place Oreostemma in a basal position relative to most other North American Aster s. lat.; data of Noyes and Rieseberg (1999) indicate that Oreostemma may be more closely related to the Machaerantherinae.

 

references

 

Cronquist, A. 1948. A revision of the Oreastrum group of Aster. Leafl. West. Bot. 5:73–82.

Greene, E.L. 1896. Studies in the Compositae. – IV. Pittonia 3:146–149.

Greene, E.L. 1900. Corrections in nomenclature – III. Pittonia 4:224.

Nesom, G.L. 1993. The genus Oreostemma (Asteraceae: Astereae). Phytologia 74:305–316.

Nesom, G.L. 1994. Review of the taxonomy of Aster sensu lato (Asteraceae: Astereae), emphasizing the New World species. Phytologia 77:141–297.

Noyes, R.D. and L.H. Rieseberg. 1999. ITS sequence data support a single origin of North American Astereae (Asteraceae) and reflect deep geographic divisions in Aster s.l. Amer. J. Bot. 86:398–412.

Xiang, C. and J.C. Semple. 1996. Molecular systematic study of Aster s. lat. and related genera (Asteraceae: Astereae) based on chloroplast DNA restriction site analyses and mainly North American taxa. In D.J.N. Hind and H.J. Beentje (eds.). Compositae: Systematics. Vol. 1, pp. 393–423. Proc. Interntl. Compositae Conf., Kew, 1994.

 

64. ORITROPHIUM (Kunth) Cuatr., Ciencia (Mιxico) 21:21. 1961.

 

Aster sect. Oritrophium Kunth in H.B.K., Nov. Gen. Sp. 4: [folio] 70, [quarto] 89. 1820.

Erigeron sect. Oritrophium (Kunth) Benth. & J.D. Hook., Gen. Pl. 2:280. 1873.

Celmisia sect. Oritrophium (Kunth) Solbrig, Contr. Gray Herb. 188:85. 1960.

 

Perennial herbs, from a thick, vertical to horizontal, fibrous-rooted rhizome, the stems unbranched, erect to decumbent, 1–30 cm tall, scapose or leafy. Leaves mostly in a basal rosette, oblanceolate to linear, 2–20 cm long, the margins entire to serrate, commonly revolute, lower petiole margins commonly producing a copious amount of persistent, long, silvery-silken hairs that appear to protrude from the root crown, the blades glabrous or silky. Heads solitary; involucres subhemispheric to broadly or cylindric-turbinate, 8–13 mm high; phyllaries in 2–5 graduated series, linear to oblong-lanceolate, slightly convex and not at all carinate, graduated or relatively even in length; receptacles flat, foveolate, epaleate. Ray florets pistillate, fertile, in 1–2 series, the lamina conspicuously longer than the involucre, white, apically coiling. Disc florets functionally staminate, with sterile ovaries, the corollas narrowly funnelform, with triangular lobes equal in length, erect; style branches linear, densely long-papillate, without stigmatic lines. Ray cypselae fusiform, 2–4 mm long, 5-veined, several-angled or compressed, glabrous to densely sericeous, eglandular; disc cypselae sterile, linear, 4–5 veined; pappus of a single series of numerous, subequal, barbellate bristles. Base chromosome number, x=9. (Greek, oros, mountain, trophe, food, nourishment )

Lectotype species (Cuatrecasas 1961): Oritrophium peruvianum (Lam.) Cuatr.

      Two Mexican species of Oritrophium are the only known representatives of the genus outside of South America (Nesom 1992, 1998). The other 20 species are endemic to high elevation habitats primarily in Venezuela and Colombia, but the genus continues southward along the Andean cordillera into Ecuador, Peru, and Bolivia (Cuatrecasas 1997; Sklenar & Robinson 2000). Plants of Oritrophium are recognized as monocephalous herbs producing a basal rosette of elongate leaves, with copiously elaborated, thin, nearly floccose indument of white hairs in the axils of the basal leaves, a lack of long, uniseriate, thick-walled trichomes, white rays, functionally staminate disc florets (with sterile ovaries and associated features of the style branches), and phyllaries with inconspicuous venation.

 

references

 

Aristeguieta, L. 1964. Oritrophium. Flora de Venezuela 10:299–309.

Cuatrecasas, J. 1961. Notas sobre Astereas Andinas. Ciencia (Mιxico) 21:21–32.

Cuatrecasas, J. 1969. Oritrophium. Prima flora Colombiana. 3. Compositae – Astereae. Webbia 24:71–90.

Cuatrecasas, J. 1997. Synopsis of the neotropical genus Oritrophium (Asteraceae: Astereae). BioLlania, Ediciσn Especial 6:287–303.

Nesom, G.L. 1992. Oritrophium orizabense (Asteraceae: Astereae), a new species and the first report of the genus from North and Central America. Phytologia 73:338–344.

Nesom, G.L. 1998. A second species of Oritrophium (Asteraceae: Astereae) from Mexico. Sida 18:523–526.

Sklenar, P. and H. Robinson. 2000. Two new species in Oritrophium and Floscaldasia (Astereae: Astereae) from the high Andes of Ecuador. Novon in press.

 

65. OSBERTIA Greene, Erythea 3:14. 1895.

 

Haplopappus sect. Osbertia (Greene) H.M. Hall, Carnegie Inst. Wash. 389:33. 1928.

 

Perennial, rhizomatous herbs, one species also stoloniferous, pilose and eglandular to puberulent and glandular with long, erect, stipitate-glandular trichomes with colored cross-walls. Stems usually single, erect. Basal leaves in a well-defined rosette, linear-oblanceolate to elliptical, margins entire to coarsely crenate or serrate, the cauline remote and reduced upwards, clasping. Heads solitary on long peduncles; involucres hemispheric to turbo-campanulate, 8–15 mm high; phyllaries linear-lanceolate, numerous, in 4–6 strongly graduated series. Receptacle convex to hemispheric, deeply alveolate, epaleate. Ray florets pistillate, fertile; corollas yellow, often purplish beneath, rarely above as well, the lamina not coiling. Disc corollas yellow, the tube not sharply distinct from the throat; style branches with linear-lanceolate, hispid appendages on the upper 1/5–1/2 of the branches. Cypselae cylindric-fusiform, with 8–16 superficial nerves, appressed villous; carpopodium asymmetric; pappus uniseriate, with numerous, nearly non-barbellate bristles, a short, outer series commonly present in O. chihuahuana Turner & Sundberg. Base chromosome number, x=5. (For British biologist Osbert Salvin, 1835–1898, who collected plants in Guatemala.)

      Type species: Osbertia stolonifera (DC.) Greene.

      A genus of three species nearly restricted to Mexico – O. stolonifera extends into Guatemala. Osbertia is recognized by its rhizomatous habit, persistent basal leaves, uniseriate, long, thin-walled, and vitreous trichomes, solitary heads with linear-lanceolate, herbaceous phyllaries in 4–6 strongly graduated series, linear-lanceolate style appendages, yellow (sometimes reddish-tinged) ray florets with non-coiling lamina, and subterete, multi-nerved cypselae with a uniseriate pappus. The genus is a member of the goldenaster group, most closely related to Chrysopsis among its North American relatives, based on morphological evidence (Nesom 1991a). Recent cpDNA studies (Lane et al. 1996), however, place Osbertia closer to the Machaerantherinae. The western species, O. chihuahuana Turner & Sundb., was transferred to Heterotheca by Turner, but his original judgement (with Sundberg) regarding its generic position apparently is correct. Another species was recently transferred to Osbertia from Heterotheca (Nesom 1991b).

 

references

 

Greene, E.L. 1895. Observations on the Compositae. – VIII. Erythea 3:6–15.

Hall, H.M. 1928. The genus Haplopappus – A phylogenetic study in the Compositae. Section 1. Osbertia. Carnegie Inst. Washington Publ. No. 389:33, 48–53.

Lane, M.A., D.R. Morgan, Y. Suh, B.B. Simpson, and R.K. Jansen. 1996. Relationships of North American genera of Astereae, based on chloroplast DNA restriction site data. In D.J.N. Hind and H.J. Beentje (eds.). Compositae: Systematics. Vol. 1, pp. 49–77. Proc. Interntl. Compositae Conf., Kew, 1994.

Nesom, G.L. 1991a. A phylogenetic hypothesis for the goldenasters (Asteraceae: Astereae). Phytologia 71:136–151.

Nesom, G.L. 1991b. Transfer of Heterotheca bartlettii to Osbertia (Asteraceae: Astereae). Phytologia 71:132–135.

Turner, B.L. and S.D. Sundberg. 1986. Systematic study of Osbertia (Asteraceae–Astereae). Pl. Syst. Evol. 151:229–239.

 

66. PENTACHAETA Nutt., Trans. Amer. Philos. Soc. 2, 7:336. 1841.

 

Annual, taprooted herbs, inconspicuously hairy, the stems simple or branching on the lower half of the plant, 3–50 cm high. Leaves alternate, narrowly oblanceolate to linear or filiform, 1–5 cm long, entire, ciliate. Heads terminal and solitary, pedunculate, radiate or discoid; involucres campanulate, 3–7 mm long; phyllaries imbricate in 2 equal or 3 unequal series, herbaceous with a broad, sharply delimited, hyaline margin; receptacles weakly foveolate. Ray florets pistillate, fertile, corollas white, yellow, or reddish, eligulate or ligulate, lamina coiling at maturity. Disc florets perfect, fertile, the corollas tubular-funnelform, with 3 or 5 shallow lobes; style branches with linear-lanceolate collecting appendages. Cypselae terete to slightly compressed, oblanceolate in outline, 1.5–3 mm long, strigose; pappus 1-seriate, of 3–5 (ca. 5), ca. 10, or ca. 20 barbellate bristles, these sometimes flared at the base and partially connate, or sometimes completely lacking. Base chromosome number, x=9. (Greek, pente, five, chaite, long hair, alluding to the 5 pappus bristles of the type species.)

      Type species: Pentachaeta aurea Nutt.

      All six species of Pentachaeta are restricted to California and adjacent Baja California. These are small, slender annuals with linear, entire, ciliate leaves, solitary, mostly yellow-rayed heads, and pappus elements in multiples of fives. Keck (1958) united Pentachaeta with Chaetopappa, but the study of Van Horn (1973) indicated that they are more distantly related. Most prominently, Chaetopappa differs in its white (to bluish) rays and base chromosome number of x=8. Nesom (1994) placed Pentachaeta as most closely related to other chiefly Californian annuals, Rigiopappus and Tracyina, a relationship earlier postulated by Blake (1937).

 

references

 

Blake, S.F. 1937. Tracyina, a new genus of Asteraceae from northern California. Madrono 4:73–77.

Keck, D.D. 1958. Taxonomic notes on the California flora. Aliso 4:102–103.

Nesom, G.L. 1994. Subtribal classification of the Astereae (Asteraceae). Phytologia 76:193–274.

Nuttall, T. 1841. Descriptions of new species and genera of plants in the natural order of the Compositae, collected ... during the years 1834 and 1835. Trans. Amer. Philos. Soc. 2, 7:283–453.

Van Horn, G.S. 1973. The taxonomic status of Pentachaeta and Chaetopappa with a revision of Pentachaeta. Univ. of California Publ. Bot. 65:1–41.

 

67. PETRADORIA Greene, Erythea 3:13. 1895.

 

Suffrutescent herbs from a stout taproot and woody, often branching caudex, the stems 0.8–3 dm high. Leaves basal and cauline, the basal persistent in a rosette, the cauline similar and little reduced upward, stiffly erect or ascending, alternate, linear to lanceolate or oblanceolate, 2–12 cm long, coriaceous, with conspicuously raised venation, the blades with 3–5 parallel veins, punctate and resinous, the margins entire and scabrous. Heads numerous, short-pedicellate in a terminal, relatively dense, paniculate-corymboid cluster; involucres cylindric to cylindric-turbinate, 5–9.5 mm high; phyllaries in 3–6 graduate series, ovate to oblong with truncate or attenuate apices, usually in vertical ranks, weakly keeled or not; receptacles alveolate, flat, epaleate. Ray florets 1–3, pistillate, fertile, yellow, 5–9 mm long. Disc florets (1–)2–4(–5) and functionally staminate, tubular-funnelform with lanceolate lobes; style branches with linear-lanceolate collecting appendages. Cypselae cylindric to slightly compressed, 4–5 mm long, 6–9 nerved, glabrous; pappus of numerous, apically attenuate, barbellate bristles in 2–3 series. Base chromosome number, x=9. (Greek, petra, a rock, and “Doria, an early name for the Goldenrod,” conveying Greene’s accurate impression that “it is found only in very stony ground or on bleak ledges.”)

      Type species: Petradoria pumila (Nutt.) Greene.

      A monotypic genus of the southwestern United States, recognized by its few-flowered, radiate, closely clustered, cylindric to cylindric-turbinate heads, functionally staminate disc florets, and phyllaries tending to be in vertical ranks. It is distinguished (fide Anderson 1963) from its putatively close relative Chrysothamnus by its suffrutescent habit of mostly annual stems and rigid, more or less persistent leaves. Anderson treated P. graminea Woot. & Standl. as a subspecies of P. pumila, but the two entities are sympatric (the range of P. graminea lies within that of P. pumila) and although morphological differences are mostly quantitative, intermediates apparently are few. Treatment of P. graminea at specific rank may prove to be more appropriate.

      Concluding a detailed study of anatomy and cytology, Anderson (1963) broadened Petradoria by including Chrysothamnus gramineus Hall (as P. discoidea L.C. Anderson, nom. nov.), based on its greater similarity to P. pumila than to C. vaseyi (A. Gray) Greene, its morphologically closest point in Chrysothamnus. In the description of the new species C. eremobius L.C. Anderson (1983), however, Anderson noted that because of its remarkable floral and vegetative similarities to P. discoidea, the latter might be moved back into Chrysothamnus alongside C. eremobius as a new group at sectional rank, a suggestion he followed in publication of his overview of Chrysothamnus (Anderson 1986). Cronquist (1994) followed this by treating Petradoria as monotypic, emphasizing the presence of ray florets and functionally staminate disc florets and placing P. discoidea back into Chrysothamnus (as C. gramineus). In contrast, in view of the otherwise strongly overlapping morphologies of these species (and including those of Hesperodoria and Vanclevea), it seems reasonable that even the monotypic Petradoria s. str. be included within Chrysothamnus, as suggested by Baird (see comments on Chrysothamnus).

 

references

 

Anderson, L.C. 1963. Studies on Petradoria (Compositae): anatomy, cytology, taxonomy. Trans. Kansas Acad. Sci. 66:632–684.

Anderson, L.C. 1983. Chrysothamnus eremobius (Asteraceae): a new species from Nevada. Brittonia 35:23–27.

Anderson, L.C. 1986. An overview of the genus Chrysothamnus (Asteraceae). Pp. 29–45 in E.D. McArthur and L. Bruce (compilers). Proceedings – symposium on the biology of Artemisia and Chrysothamnus. General Technical Report INT-200, U.S.D.A., Forest Service, Ogden, Utah.

Cronquist, A. 1994. Intermountain flora. Vol. 5, Asterales. The New York Botanical Garden, Bronx.

Greene, E.L. 1895. Observations on the Compositae. –VIII. Erythea 3:6–15.

Nesom, G.L. and G.I. Baird. 1993. Completion of Ericameria, (Asteraceae: Astereae), diminution of Chrysothamnus. Phytologia 75:74–93.

 

68. PITYOPSIS Nutt., Trans. Amer. Philos. Soc. 2, 7:317. 1841.

 

Chrysopsis sect. Pityopsis (Nutt.) Torr. & A. Gray, Fl. N. Amer. 2:252. 1842.

Heterotheca sect. Pityopsis (Nutt.) Harms, Castanea 34:402. 1969.

Heyfeldera Schultz-Bip., Flora 36:35. 1853.

 

Herbaceous perennials from a short, fibrous-rooted rhizome, 1–8 dm tall, the stems and leaves silky-sericeous with mostly appressed, anastomosing hairs, often stipitate-glandular. Leaves alternate, linear to lanceolate or oblanceolate, 1–40 cm long, entire, parallel veined, sometimes falcate, mostly basal or basal and cauline, the cauline reduced upwards. Heads few to many in an open, corymboid arrangement; involucres mostly cylindric-turbinate, 5–11(–13) mm high; phyllaries lanceolate, in 4–8 graduate series, usually with a distinct, apical green patch. Ray corollas pistillate, fertile, 8–35, yellow, coiling with maturity. Disc corollas perfect, fertile, gradually ampliate, the lobes deltate, erect. Cypselae fusiform, 2–5 mm long, terete to slightly compressed, strigose; pappus 2-seriate, the inner of barbellate bristles, the outer of much shorter setiform bristles or setae. Base chromosome number, x=9. (Greek, pitys, pine, and -opsis, appearance or likeness, for a perceived similarity of the type species to pine, perhaps to longleaf pine, which has a grass-like habit in early growth stages.)

      Type species: Pityopsis pinifolia (Ell.) Nutt.

      Pityopsis is a genus of about seven species mostly restricted to the southeastern United States, with only one ranging into Mexico and Central America along the Gulf Coastal Plain (Semple and Bowers 1985). It has been traditionally included in Chrysopsis or Heterotheca, but there is evidence (Semple et al. 1980) for maintaining it as a separate genus distinguished by its parallel-veined, grass-like leaves, silky-sericeous vestiture, fusiform cypselae, and base chromosome number of x=9. On the basis of morphology, it is hypothesized to be the sister group to Croptilon (Nesom 1991).

 

references

 

Dress, W. 1953. A revision of the genus Chrysopsis in eastern North America. Ph.D. diss., Cornell Univ., Ithaca, NY.

Nesom, G.L. 1991. A phylogenetic hypothesis for the goldenasters (Asteraceae: Astereae). Phytologia 71:136–151.

Nuttall, T. 1841. Descriptions of new species and genera of plants in the natural order of the Compositae, collected ... during the years 1834 and 1835. Trans. Amer. Philos. Soc. 2, 7:283–453.

Semple, J.C. 1985. New names and combinations in Compositae, tribe Astereae. Phytologia 58:429–431.

Semple, J.C., V. Blok, and P. Heiman. 1980. Morphological, anatomical, habit, and habitat differences among the goldenaster genera Chrysopsis, Heterotheca and Pityopsis (Compositae – Astereae). Canad. J. Bot. 58:164–171.

Semple, J.C. and F.D. Bowers. 1985. A revision of the goldenaster genus Pityopsis Nutt. (Compositae: Astereae). Univ. of Waterloo Biol. Ser. 29:1–34.

Semple, J.C. and F.D. Bowers. 1987. Cytogeography of Pityopsis Nutt., the grass-leaved goldenasters (Compositae: Astereae). Rhodora 89:381–389.

 

69. PSILACTIS A. Gray, Mem. Amer. Acad. Arts 2, 4:71 [Pl. Fendler. 71]. 1849.

 

Machaeranthera sect. Psilactis (A. Gray) Turner & Horne, Brittonia 16:321. 1964.

 

Taprooted annual or perennial herbs (rhizomatous in P. odysseus (Nesom) Morgan), 1–15 dm tall, stems and phyllaries (and often the leaves) stipitate-glandular, sometimes also sparsely tomentose. Basal and lower cauline leaves obovate to linear-lanceolate, 2–10 cm long, usually deciduous by flowering, middle and upper cauline entire, subclasping. Heads in a loosely paniculate to corymboid inflorescence (stems monocephalous in P. odysseus); involucres broadly turbinate to hemispheric, 2–9 mm high; phyllaries in 2–4 subequal to strongly graduate series, the outer indurated along the basal margins. Ray florets pistillate, fertile, the lamina white to bluish, 1.5–14 mm long, tightly coiling at maturity. Disc florets perfect, fertile, narrowly tubular, 1.5–4.5 mm long. Ray cypselae fusiform to obovate, 1–1.8 mm long, subterete, 5–14(–18) nerved, moderately short-strigose, epappose, the disc cypselae similar but 1.3–3 mm long (usually slightly longer than the ray) and pappose with a single series of barbellate bristles. Base chromosome numbers, x=9, 4, 3. (Greek, psilos, bare, aktis, ray, in reference to the epappose ray cypselae.)

      Type species: Psilactis asteroides A. Gray.

      A genus of six species previously treated within Machaeranthera (Turner & Horne 1964). Morgan (1993) resegregated Psilactis at generic rank, particularly emphasizing molecular (chloroplast DNA) evidence suggesting a relationship to North American genera traditionally placed within Aster, particularly Symphyotrichum (see comments in Nesom 1994). Species of Psilactis have not yet been included in molecular analyses of Aster s. lat., but resolution of its phyletic placement may be expected to have bearing on the interpretations of phylogeny and taxonomic rank for Almutaster, Symphyotrichum sect. Oxytripolium, and Symphyotrichum sect. Virgulus.

      One species of Psilactis is endemic to a small coastal area of southeastern Texas; the five others are chiefly Mexican, although the ranges of three of them touch northward into the USA. Psilactis brevilingulata Schultz-Bip. ex Hemsl. has disjunct stations in northwestern South America (Cuatrecasas 1969). All species tend to inhabit moist or wet habitats and as a group are recognized by their taprooted habit, stipitate-glandular vestiture, clasping to subclasping cauline leaves, white to bluish rays, epappose ray cypselae, and base chromosome number of x=4, reduced to x=3. The narrowly endemic P. odysseus (Nesom) Morgan, which is the most primitive species based on molecular evidence (Morgan 1993), is unusual in its rhizomatous habit, monocephalous stems, and chromosome number of 2n=18.

 

references

 

Cuatrecasas, J. 1969. Psilactis. Prima flora Colombiana. 3. Compositae – Astereae. Webbia 24:65–71.

Gray, A. 1849. Plantae Fendlerianae Novi-Mexicanae: an account of a collection of plants made chiefly in the vicinity of Santa Fe, New Mexico, by Augustus Fendler. Mem. Amer. Acad. Arts 2, 4:1–116.

Hartman, R.L. and M.A. Lane. 1987. A new species of Machaeranthera section Psilactis (Asteraceae: Astereae) from coastal Texas. Brittonia 39:253–257.

Morgan, D.R. 1993. A molecular systematic study and taxonomic revision of Psilactis (Asteraceae: Astereae). Syst. Bot. 18:290–308.

Nesom, G.L. 1978. Machaeranthera odyssei (Compositae): a unique new species from Mexico. Syst. Bot. 3:218–225.

Nesom, G.L. 1994. Review of the taxonomy of Aster sensu lato (Asteraceae: Astereae), emphasizing the New World species. Phytologia 77:141–297.

Stucky, J. 1974. A biosystematic study of Machaeranthera sect. Psilactis and selected species of Aster. Ph.D. diss., Texas Tech Univ., Lubbock.

Turner, B.L. and D. Horne. 1964. Taxonomy of Machaeranthera sect. Psilactis (Compositae–Astereae). Brittonia 16:316–331.

 

70. PYRROCOMA Hook., Fl. Bor.-Amer. 1:306. 1833.

 

Haplopappus sect. Pyrrocoma (Hook.) H.M. Hall, Carnegie Inst. Wash. 389:34. 1928.

Homopappus Nutt., Trans. Amer. Philos. Soc. 2, 7:330. 1841.

Haplopappus sect. Arnicella Torr. & A. Gray, Fl. N. Amer. 2:241. 1842.

 

Perennial herbs from a woody taproot and often a short, branched caudex, with decumbent to ascending or erect, often red-tinged stems 5–20 cm high, stems, leaves, and phyllaries sericeous, tomentose, or glabrous, sometimes sessile- or stipitate-glandular. Leaves simple, cauline or basal and cauline, the basal oblanceolate to elliptic or nearly linear, 3–25(–45) cm long, uncommonly with a short petiole, entire to spinulose-dentate or -serrate or shallowly laciniate, the cauline alternate, clasping to subclasping, reduced upwards. Heads solitary, racemoid to spiciform, or loosely corymboid; involucres hemispheric to narrowly campanulate, 5–15(–20) mm high; phyllaries in 2–6 equal to graduate series, oblanceolate to oblong or linear, herbaceous and yellow-green throughout or with a distinct, green, apical patch, or less commonly the lower 2/3 white-indurate. Ray florets 10–80, the corollas yellow, mostly 10–35 mm long, sometimes greatly reduced and not exceeding the involucre. Disc florets perfect, fertile, the corollas tubular-funnelform, lobes deltate, erect; style branches with triangular collecting appendages. Cypselae subcylindric-fusiform, 3–8 mm long, terete to somewhat flattened, 3–4 angled, with several nerves between the angles, sericeous to strigose or glabrous; pappus of comparatively few, brownish, rigid bristles of unequal length. Base chromosome number, x=6. (Greek, pyrrhos, reddish or tawny, kome, hair of the head, in reference to the reddish pappus in some species.)

      Type species: Pyrrocoma carthamoides Hook.

      A genus of about 14 species (some with infraspecific variants) in the western United States and Canada. It usually has been included at sectional rank within Haplopappus but the definition of Pyrrocoma is sharp. It was treated as a separate genus by Mayes (1976) and apparently for the first time in a floristic manual by Brown (1993). Pyrrocoma is recognized by a persistent basal rosette, yellow-rayed heads on nearly scapose stems or few-bracted peduncles, and obtuse, acute, or mucronate involucral bracts. The heads vary greatly in size and commonly are sessile or subsessile and borne in a spicate inflorescence. Evidence from cpDNA analyses (Morgan & Simpson 1992) aligns Pyrrocoma most closely with Machaeranthera sect. Arida (within the cladistic topology of Machaeranthera) while ITS studies of nuclear ribosomal DNA (Morgan 1997) place Pyrrocoma outside of Machaeranthera s. lat., closer to Hazardia, Lessingia, the Xanthocephalum group, and Haplopappus s. str.

 

references

 

Brown, G.K. 1993. Pyrrocoma. Pp. 330–331 in J.C. Hickman (ed.). The Jepson manual: Higher plants of California. Univ. of California Press, Berkeley.

Hall, H.M. 1928. The genus Haplopappus – A phylogenetic study in the Compositae. Section 5. Pyrrocoma. Carnegie Inst. Washington Publ. No. 389:34, 95–156.

Mayes, R.A. 1976. A cytotaxonomic and chemosystematic study of the genus Pyrrocoma (Asteraceae: Astereae). Ph.D. diss., Univ. of Texas, Austin.

Morgan, D.R. 1997. Reticulate evolution in Machaeranthera (Asteraceae). Syst. Bot. 22:599–615.

Morgan, D.R. and B.B. Simpson. 1992. A systematic study of Machaeranthera (Asteraceae) and related groups using restriction site analysis of chloroplast DNA. Syst. Bot. 17:511–531.

 

71. RAYJACKSONIA Hartman & Lane, Amer. J. Bot. 83:368. 1996,

 

Annual to perennial herbs from taproots, main stems erect, 0.4–8 dm tall, basally branching and leafy throughout, the leaves, stems, and phyllaries prominently sessile- to stipitate-glandular. Leaves linear to oblanceolate, 1–8 cm long, the margins coarsely serrate with bristle-tipped teeth. “Heads 1–3 on primary stems and lateral branches, 1–70 or more per plant, the whole often appearing paniculate or subcorymbiform-cymose, peduncles somes cobwebby" (Lane and Hartman 1996); involucres hemispheric, 7–16 mm high; phyllaries linear to lanceolate, 1-nerved, in 4–5 equal to subequal series, the apices erect or loosely spreading or recurved; receptacles alveolate. Ray florets pistillate, fertile, 18–46, the lamina yellow, 9–15 mm long. Disc florets perfect, fertile, corollas 5–7 mm long, the tube abruptly ampliate into the throat, lobes erect to slightly spreading; style branches with deltate collecting appendages. Cypselae strigose-sericeous, dimorphic: ray cypselae 1.5–2 mm long, broadly ellipsoid to obovoid, thick-walled, 3-angled, the faces with 0–4 ribs; disc cypselae broadly ellipsoid to clavate, somewhat radially compressed, thinner-walled, the faces with 5–9 ribs; pappus of barbellate, thick-flattened, persistent bristles in 3–4 series of unequal length, about as long as the disc corollas. Base chromosome number, x=6. (For contemporary American botanist and plant geneticist Raymond C. Jackson.)

      Type species: Rayjacksonia phyllocephala (DC.) Hartman & Lane.

      Hartman (1990, following his earlier Ph.D. dissertation) informally recognized the three species of Rayjacksonia as an undescribed genus most closely related to Xanthocephalum, Isocoma, Grindelia, and other genera of Machaerantherinae, particularly those with x=6. The taxonomy was formalized by Lane and Hartman (1996). The Rayjacksonia species are coherent in vestiture, spinulose foliar teeth, solitary heads, ray florets with prominent yellow lamina, and chromosome number of n=6, but morphological features that could be interpreted as specialized among their close generic relatives are subtle. Two of the species are endemic to the central and south-central USA; R. phyllocephala reaches into northeastern Mexico.

 

references

 

Hartman, R.L. 1990. A conspectus of Machaeranthera (Asteraceae: Astereae). Phytologia 68:439–465.

Jackson, R.C. and C.T. Dimas. 1981. Experimental evidence for systematic placement of the Haplopappus phyllocephalus complex (Compositae). Syst. Bot. 6:8-14.

Lane, M.A. and R.L. Hartman. 1996. Reclassification of North American Haplopappus (Compositae: Astereae) completed: Rayjacksonia gen. nov. Amer. J. Bot. 83:356–370.

 

72. REMYA Hillebrand ex Benth. in Benth. & J.D. Hook., Gen. Pl. 2:pars prima Addend. 536. 1873; Gen. Pl. 2:1231. 1876.

 

Shrubs, densely tomentose to glabrous, the stems branching, 1–4 m long, weakly erect or forming loosely tangled, sprawling clumps. Leaves simple, alternate, produced near the ends of stems or more evenly distributed, narrowly elliptic to broadly ovate or lanceolate, 5–18 cm long, short-petiolate, glabrous or white-tomentose beneath, the margins serrate to dentate. Heads disciform, terminal, loosely corymboid, sometimes somewhat rounded; involucres ovoid to globose or hemispheric, 2–5 mm high; phyllaries in 4–5 graduate series; receptacles convex, alveolate, without chaff. Ray florets pistillate, fertile, 12–20, the corollas with cream-colored rays barely longer than the involucre. Disc florets of 1 or 2 types: those in the outer whorl with tubular corollas, lacking stamens, the ovaries sterile fertile or pistillate, the inner with goblet-shaped corollas, functionally staminate. Cypselae narrowly obovoid, 1.5–1.8 mm long, compressed but 3–4 angled with 1–2 nerves on each face, glabrous to sparsely short-strigose; pappus of fertile cypselae of 3–9(–14) stiff, unequal to subequal, persistent, somewhat flattened, non-barbellate bristles, sometimes reduced on sterile ovaries. Base chromosome number, x=9. (For French naturalist and traveler Ezechiel Jules Rιmy, 1826–1893, who collected in Hawaii from 1851 to 1855.)

      Type species: Remya mauiensis Hillebr.

      A genus of three species, all endemic to the Hawaiian Islands of Kaua’i and Maui. Each of the species is known from one or a few populations. Wagner and Herbst (1987) hypothesized that Remya is most closely related to the large Australasian genus Olearia Moench, placed by Nesom (1994) in the subtribe Hinterhuberinae. The two genera have in common a shrubby habit, relatively thick leaves, tendency for tomentose vestiture, and heads in loose corymbs. “Remya differs from Olearia primarily in its liana habit, monoecious heads, and reduced pappus of 3–9(14) non-barbellate bristles.” The tendency for partial or complete sterility of the disc florets, as seen in Remya, is relatively common in genera of Hinterhuberinae (Nesom 1993, 1994).

 

references

 

Nesom, G.L. 1993. Aztecaster (Asteraceae: Astereae), a new ditypic genus of dioecious shrubs from Mexico with redefinitions of the subtribes Hinterhuberinae and Baccharidinae. Phytologia 75:55–73.

Nesom, G.L. 1994. Subtribal classification of the Astereae (Asteraceae). Phytologia 76:193–274.

Wagner, W.L. and D.R. Herbst. 1987. A new species of Remya (Asteraceae: Astereae) on Kaua’i and a review of the genus. Syst. Bot. 12:601–608.

 

73. RIGIOPAPPUS A. Gray, Proc. Amer. Acad. Arts 6:548. 1865.

 

Taprooted annuals 1–3 dm tall, hirsutulous, the stems simple or with a few lateral branches overtopping the main axis. Leaves alternate, ascending to erect, linear, 1–3 cm long, entire, the lower usually deciduous. Heads terminal, solitary on long, slender, leafy or few-bracteate peduncles; involucres broadly turbinate, 4–8 mm high; phyllaries in 2 subequal series, hirsutulous, linear-oblong to lanceolate, apically acute with narrow, hyaline margins, partially clasping the outer (ray and disc) cypselae; receptacle chaffy between the ray and disc florets. Ray florets mostly 3, 5, or 8(–15), rarely absent, the corollas yellow, often purple-tinged, 1.5–2.5 mm long. Disc florets perfect, fertile, the corollas narrowly cylindric, with 2–4 deltate lobes; style branches with linear-lanceolate collecting appendages. Cypselae narrowly cylindric to slightly fusiform or slightly compressed, 3.5–4 mm long, apically truncate, strigose with apcially clavate duplex hairs, transversely rugose; pappus of (0–)3–5, stiff, white, tapered scales 2–3.5 mm long. Base chromosome number, x=9. (Greek, rigios, rigid, and pappus, in reference to the stiff pappus bristles.)

      Type species: Rigiopappus leptocladus A. Gray.

      A monotypic genus endemic to grassland and shrublands of the northwestern United States, recognized by taprooted, annual habit, linear leaves, few, solitary heads with few, equal phyllaries and inconspicuous yellow rays, and narrow cypselae with stiff pappus scales. Artificially produced hybrids between Rigiopappus and Tracyina were largely sterile (ca. 33% pollen viability, infertile cypselae) but showed a high degree of chromosomal homology in meiotic pairing (Ornduff & Bohm 1975). Blake (1937) observed the close resemblance and probable interrelationship of Rigiopappus, Tracyina, and Pentachaeta. Robinson and Brettell (1973) reviewed morphological evidence indicating that these three genera are members of Astereae rather than Helenieae. Additional background on the placement of Rigiopappus in the Astereae is provided by Turner and Powell (1977).

 

references

 

Blake, S.F. 1937. Tracyina, a new genus of Asteraceae from northern California. Madrono 4:73–77.

Gray, A. 1865. Characters of some new plants of California and Nevada ... with revisions of certain genera or groups. Proc. Amer. Acad. Arts 6:519–556.

Ornduff, R. and B.A. Bohm. 1975. Relationships of Tracyina and Rigiopappus. Madrono 23:53–55.

Robinson, H. and R.D. Brettell. 1973. Tribal revisions in the Asteraceae. V. The relationship of Rigiopappus. Phytologia 26:69–70.

Turner, B.L. and A.M. Powell. 1977. Helenieae – systematic review. In V.H. Heywood, J.B. Harborne, and B.L. Turner (eds.). The Biology and Chemistry of the Compositae 2:699–737. Academic Press, London.

 

74. SERICOCARPUS Nees, Gen. Sp. Aster. 148. 1832 [1833].

 

Aster sect. Sericocarpus (Nees) A.G. Jones, Brittonia 32:238. 1980.

Aster sect. Sericocarpus (Nees) Semple, Phytologia 58:429. 1985.

Oligactis Raf., Fl. Tellur. 2:44. 1836 [non Oligactis (Kunth) Cass. 1825].

Aster sect. Serratifolii G. Don, Hort. Brit. 347. 1830.

Aster sect. Leucoma Nutt., J. Acad. Nat. Sci. Philadelphia 7:82. 1834.

 

Perennial, erect herbs 2–12 dm tall, from a short, thickened rhizome with fibrous roots, with thin, stoloniform rhizomes in several entities, glandular and otherwise glabrous to puberulent. Leaves basal and cauline, alternate, linear to oblanceolate or elliptic-oblanceolate, 1.5–9 cm long, sessile, the surfaces sessile- or punctate-glandular. Heads sessile or subsessile in terminal, glomerate clusters, the clusters in a distinctly flat-topped corymboid inflorescence; involucres cylindric to turbinate, 4–9 mm high; phyllaries coriaceous, in 3–6 graduate series, keeled, with a sharply delimited, basally truncate, green apical patch, whitish, indurate-thickened, and convex below; receptacle alveolate. Rays pistillate, fertile, white, 3–8, short, not coiling. Disc florets perfect, fertile, funnelform, white or cream colored, not purplish at maturity; style branches with lanceolate to linear-lanceolate, papillate collecting appendages. Cypselae narrowly obconic to nearly cylindric, 1.5–3 mm long, with ca. 4–8 partially buried nerves, strigose-sericeous; pappus in 2–3 series of barbellate, even-length, apically dilated bristles. Base chromosome number, x=9. (Greek, sericus, silky, karpos, fruit.)

      Lectotype species (Britton & Brown 1913): Sericocarpus linifolius (L.) B.S.P.

      A genus of five species, three in the eastern United States and two in the western United States. Sericocarpus has long been recognized as a distinct genus; it was the last group added to the broadly inclusive North American Aster s. lat. (Cronquist 1947). It was placed by Nesom (1993) as a close relative of Solidago and its relatives but later regarded as the closest relative of the North American Aster segregate Eurybia (Nesom 1994). Xiang and Semple (1996) and Semple et al. (1996) also have regarded Sericocarpus and Eurybia as closely related but have maintained both groups within Aster s. lat. In a phylogenetic analysis of Astereaean genera based on nuclear ribosomal ITS data (Noyes & Rieseberg 1999), Sericocarpus is most closely related to Solidago and Chrysothamnus; species of Eurybia were not represented in this study. Sericocarpus is distinguished from Eurybia and other potentially closely related genera in its combination of glandular leaves, glomerate heads in a corymboid aggregate, green-tipped phyllaries, white ray and disc florets, sericeous cypselae, and base chromosome number of x=9.

 

references

 

Bigger, D.S. 1999. Consequences of patch size and isolation for a rare plant: Pollen limitation and seed predation. Natural Areas J. 19:239–244. [Aster curtus]

Britton, N.L. and A. Brown. 1913. An illustrated flora of the northern United States, Canada, and the British Possessions (ed. 2). Vol. 3. Lancaster Press, Lancaster, Penn.

Cronquist, A. 1947. Notes on the Compositae of the northeastern United States – V. Astereae. Bull. Torrey Bot. Club 74:142–150.

Douglas, G.W. and J.M. Illingworth. 1997. Status of the white-top Aster, Aster curtus (Asteraceae) in Canada. Canad. Field-Nat. 111:662–627.

Giblin, D.E. and C.W. Hamilton. 1999. The relationship of reproductive biology to the rarity of endemic Aster curtus (Asteraceae). Canad. J. Bot. 77:140–149.

Nesom, G.L. 1993. Taxonomy of Sericocarpus (Asteraceae: Astereae). Phytologia 75:45–54.

Nesom, G.L. 1994. Review of the taxonomy of Aster sensu lato (Asteraceae: Astereae), emphasizing the New World species. Phytologia 77:141–297.

Noyes, R.D. and L.H. Rieseberg. 1999. ITS sequence data support a single origin of North American Astereae (Asteraceae) and reflect deep geographic divisions in Aster s.l. Amer. J. Bot. 86:398–412.

Semple, J.C., S.B. Heard, and C.S. Xiang. 1996. The Asters of Ontario (Compositae: Astereae): Diplactis Raf., Oclemena E.L. Greene, Doellingeria Nees and Aster L. (including Canadanthus Nesom, Symphyotrichum Nees, and Virgulus Raf.). Rev. ed. Univ. of Waterloo Biol. Ser. 38:i–viii, 1–94.

Xiang, C. and J.C. Semple. 1996. Molecular systematic study of Aster s. lat. and related genera (Asteraceae: Astereae) based on chloroplast DNA restriction site analyses and mainly North American taxa. In D.J.N. Hind and H.J. Beentje (eds.). Compositae: Systematics. Vol. 1, pp. 393–423. Proc. Interntl. Compositae Conf., Kew, 1994.

 

75. SOLIDAGO L., Sp. Pl. 878. 1753.

 

Amphiraphis DC., Prodr. 5:343. 1836.

Actipsis Raf., Fl. Tellur. 2:43. 1836.

Anactis Raf., Fl. Tellur. 2:44. 1836.

Brintonia Greene, Erythea 3:89. 1895.

Brachychaeta Torr. & A. Gray, Fl. N. Amer. 2:194. 1842.

 

Perennial herbs 1–20(–40) dm tall, from a fibrous-rooted rhizome or caudex, often stoloniferous, rarely from a thick taproot. Leaves alternate, linear or linear-lanceolate to obovate, 2–30(–40) cm long, prominently 3-nerved in some groups, sessile, toothed to entire, eglandular, sometimes with sessile resin glands, punctate only in S. odora Ait. and S. chapmanii Torr. & A. Gray. Heads in a paniculate to racemose-paniculate inflorescence, arranged in cylinders to pyramids, often secund on arcuate-ascending branches; involucres cylindric to turbinate, 3–6 mm high; phyllaries usually with a single, orange-glandular midrib, often with a subapical green patch; receptacle naked to foveolate, sometimes with caducous pales. Ray florets pistillate, fertile, yellow, the lamina usually coiling. Disc corollas perfect, fertile, tubular-funnelform with lanceolate lobes often longer than the throat; style branches with lanceolate collecting appendages. Cypselae fusiform-cylindric, (0.5–)0.8–4 mm long, terete to subterete, 5–8 nerved, glabrous or strigose; pappus a single series of numerous, whitish, barbellate bristles. Base chromosome number, x=9. (Latin, solidus, whole or enduring, and -ago, with characteristics of, supposedly in reference to reputed value in healing or treating of wounds.)

      Type species: Solidago virgaurea L.

      Solidago comprises about 100 species, about 80 native to North America (ca. 70 in the US and 8 restricted to Mexico) and 10–20 in Eurasia (including the generitype). One species is native to South America. The genus is recognized primarily by its rhizomatous, herbaceous habit, small, few-flowered, radiate heads in a thyrsoid or secund-paniculate inflorescence, small, multinerved, terete cypselae, and uniseriate pappus. Solidago has been divided into two sections (sect. Solidago and sect. Unilaterales G. Don) and further apportioned into numerous subsections and series, primarily on the basis of inflorescence architecture, leaf morphology and position, and elaboration of rhizomes (Nesom 1993), but morphological intergradation occurs between the categories and intersectional hybrids are not uncommon. Recent molecular data (Zhang 1966) largely confirm the proposed subsectional groupings but not the primary division of the genus into two sections (sect. Solidago vs. sect. Unilaterales).

      Many Solidago species are variable in vestiture and other characteristics and tend to form intergrading geographical varieties. Some of the taxonomic difficulties are associated with hybridization, introgression, and polyploidy. The Old World plants are particularly in need of taxonomic study. A large amount of published information exists regarding the systematics of Solidago; entry into the taxonomic literature can be accessed through references cited below and various other floristic treatments.

      The species of Oligoneuron (which see) are often treated as part of Solidago, but other groups relatively recently placed within Solidago are now more generally regarded as distinct genera (Euthamia, Chrysoma, Petradoria, Oreochrysum). Semple et al. (1999) have proposed the formal taxonomic reunion of Oreochrysum with Solidago. The proposed monotypic genera Brintonia and Brachychaeta have their closest relatives in sect. Solidago and sect. Unilaterales, respectively (sensu Nesom 1993), within Solidago.

 

references

 

Anderson, L.C. and J.B. Creech. Comparative leaf anatomy of Solidago and related Asteraceae. Amer. J. Bot. 62:486–493.

Kapoor, B.M. and J.R. Beaudry. 1966. Studies on Solidago. VII. The taxonomic status of the taxa Brachychaeta, Brintonia, Chrysoma, Euthamia, Oligoneuron and Petradoria in relation to Solidago. Canad. J. Genet. Cytol. 8:422–443.

Nesom, G.L. 1993. Taxonomic infrastructure of Solidago and Oligoneuron (Asteraceae: Astereae) and comments on their phylogenetic position. Phytologia 75:1–44.

Semple, J.C. 1992. A geographic summary of chromosome number reports for North American asters and goldenrods (Asteraceae, Astereae). Ann. Missouri Bot. Gard. 79:95–109.

Semple, J.C. and G.S. Ringius. 1983. The goldenrods of Ontario: Solidago L. and Euthamia Nutt. Univ. of Waterloo Biol. Ser. 26:1–84. Rev. ed., 1992, by J.C. Semple.

Semple, J.C., G.S. Ringius, and J.J. Zhang. 1999. The goldenrods of Ontario: Solidago L. and Euthamia Nutt. (ed. 3). Univ. of Waterloo Biol. Ser. 39:1–90.

Taylor, C.E.S. and R.J. Taylor. 1984. Solidago (Asteraceae) in Oklahoma and Texas. Sida 10:223–251.

Zhang, J.J. 1996. A molecular biosystematic study on North American Solidago and related genera (Asteraceae: Astereae) based on chloroplast DNA RFLP analysis. Ph.D. diss., Univ. of Waterloo, Waterloo, Ontario, Canada.

 

76. STENOTUS Nutt., Trans. Amer. Philos. Soc. 2, 7:334. 1841.

 

Haplopappus sect. Stenotus (Nutt.) H.M. Hall, Carnegie Inst. Wash. Publ. 389:34. 1928.

 

Perennial herbs from woody, multicipital caudices, with few-numerous, short, crowded stems 0.5–2 dm tall, glabrous to sparsely or densely tomentose, not resinous or punctate, stipitate-glandular in some. Leaves mostly in a basal rosette, entire, linear to linear-oblanceolate or nearly spatulate, 1–8 cm long, with 3, parallel, raised nerves, apparently 1-nerved in narrow leaves. Heads solitary, the peduncles leafless or less commonly with scattered leaves; involucres campanulate to hemispheric, 6–12 mm high; phyllaries herbaceous with hyaline margins, 3(–5)-nerved, strongly to weakly graduated in 2–3(–4) series; receptacles foveolate to nearly smooth. Ray florets pistillate, fertile, yellow, with broad lamina, slightly coiling at maturity, absent in S. pulvinatus (Moran) Nesom. Disc corollas perfect, fertile, yellow, gradually ampliate; style branches with triangular-lanceolate to linear-lanceolate collecting appendages. Cypselae subterete to compressed, 4–7 mm long, 2–6-nerved, moderate to densely strigose-sericeous; pappus of 1–2 series of basally caducous, subequal, barbellate bristles. Base chromosome number, x=9. (Greek, stenos, narrow, or stenotes, narrowness, alluding to the characteristically narrow leaves.)

Lectoype species (Hall 1928), Stenotus acaulis Nutt.

      A genus of six or seven species of montane habitats in Canada (including Yukon), the western USA, and Mexico (Morse 1998). The plants are herbs with a basal cluster of parallel-veined leaves, essentially scapose, monocephalous stems, and yellow-rayed heads with relatively few, subequal, 3–5-nerved phyllaries, and sericeous cypselae. Stenotus pulvinatus (Moran) Nesom is unusual in the genus in its eradiate heads and is geographically isolated in Baja California (Nesom 1989). Stenotus apparently is closely related to Chrysothamnus, in the expanded sense of the latter (i.e., including the genera Petradoria and Hesperodoria; Nesom & Baird 1993; Baird ms.). Within the genus, S. acaulis and S. amerioides Nutt. are the most similar to the Petradoria group in their leaves with strongly raised venation and in their broadly dilated phyllaries.

 

references

 

Baird, G.I. Manuscript. A redefinition of Chrysothamnus (Asteraceae: Astereae).

Hall, H.M. 1928. The genus Haplopappus – A phylogenetic study in the Compositae. Section 7. Stenotus. Carnegie Inst. Washington Publ. No. 389:34, 161–177.

Moran, R. 1969. Five new taxa of Haplopappus (Compositae) from Baja California, Mexico. Trans. San Diego Soc. Nat. Hist. 15:149–164.

Morse, C.A. 1998. Systematics and taxonomy of Stenotus Nutt. (Asteraceae: Astereae). M.A. thesis, Univ. of Kansas, Lawrence.

Nesom, G.L. 1989. A new combination in Stenotus (Compositae: Astereae). Phytologia 67:113–114.

Nesom, G.L. and G.I. Baird. 1993. Completion of Ericameria (Asteraceae: Astereae), diminution of Chrysothamnus. Phytologia 75:74–93.

Nuttall, T. 1841. Descriptions of new species and genera of plants in the natural order of the Compositae, collected ... during the years 1834 and 1835. Trans. Amer. Philos. Soc. 2, 7:283–453.

Welsh, S.L. and F.J. Smith. 1983. New Haplopappus variety in Utah (Compositae). Great Basin Nat. 43:371–372.

 

77. STEPHANODORIA Greene, Erythea 3:12. 1895.

 

Perennial herbs 0.5–1.5 dm high, from woody roots, producing short basal offsets, single-stemmed from the base, branching primarily in the inflorescence, the stems, leaves, and phyllaries stipitate-glandular and minutely hirtellous-pilosulous. Leaves with blades obovate- to oblong-elliptic, entire, the basal persistent, mostly 15–30 cm long, basally attenuate to a petiole 3–12 cm long, the cauline reduced and becoming sessile upwards. Heads sessile to short-pedunculate in compound clusters of 2–6, these in an open corymb; involucres turbinate, 4.5–6 mm long; phyllaries in 5–7 graduated series, spreading to reflexed at the tip. Ray florets ca. 20–30, golden-yellow, pistillate, fertile, the corollas 4.2–5 mm long. Disc florets perfect, fertile, yellow, the outer leaning outward after elongation of the tube; style branches with deltate-triangular collecting appendages. Cypselae oblanceolate-oblong to oblong-elliptic, strongly flattened, 2–3-nerved, 1.3–1.8 mm long, straw-colored, sparsely short-strigose at the apex, otherwise glabrous; pappus a hyaline, lacerate- or erose-margined corona 0.3–0.5 mm high, or sometimes the corona 1-sided and awn-like. Base chromosome number, x=6. (Greek, stephanos, crown, in reference to the coronal pappus, and doria, an early name for the goldenrod.)

      Type species: Stephanodoria tomentella (B.L. Rob.) Greene.

      A monotypic genus closely related to Isocoma, Grindelia, Xanthocephalum, and possibly Pyrrocoma. Stephanodoria apparently remains extant only as a few small populations in a restricted, gypseous habitat near Cerritos in central San Luis Potosν, Mexico. These plants, originally described as a species of Xanthocephalum by Robinson (1892), are recognized by their large, persistent basal leaves, leafy stems, stipitate-glandular vestiture, glomerate heads in an open corymb, numerous but inconspicuous rays, and strongly flattened cypselae with coronal pappus.

 

references

 

Greene, E.L. 1895. Observations on the Compositae. – VIII. Erythea 3:6–15.

Nesom, G.L. 1997. Synopsis of Stephanodoria (Asteraceae: Astereae). Phytologia 82:107–113.

Robinson, B.L. 1892. Descriptions of new plants collected in Mexico by C.G. Pringle in 1890 and 1891, with notes upon a few other species. Proc. Amer. Acad. Arts 27:165–185.

 

78. SYMPHYOTRICHUM Nees, Gen. Sp. Aster. 135. 1832 [1833].

 

Aster subg. Symphyotrichum (Nees) A.G. Jones, Brittonia 32:234. 1980.

Lasallea Greene, Leafl. Bot. Observ. Crit. 1:5. 1903.

Aglotoma Raf., Fl. Tellur. 2:44. 1836 [1837].

Virgaria Raf. ex DC. [pro syn.], Prodr. 5:243. 1836.

Virgulus Raf., Fl. Tellur. 2:46. 1836 [1837].

Aster subg. Virgulus (Raf.) A.G. Jones, Brittonia 32:233. 1980.

Aster subg. Ascendentes (Rydb.) Semple, Phytologia 58:430. 1985.

Virgulaster Semple, Phytologia 58:430. 1985.

Tripolium subg. Astropolium Nutt., Trans. Amer. Philos. Soc. 2, 7:295. 1841.

Tripolium sect. Oxytripolium DC., Prodr. 5:253. 1836.

Aster subg. Oxytripolium (DC.) Torr. & A. Gray, Fl. N. Amer. 2:161. 1841.

Aster sect. Heterastrum Benth. in Benth. & J.D. Hook., Gen. Pl. 2:273. 1873.

Conyzanthus Tamamsch., Fl. U.R.S.S. 24:583. 1959.

Fimbristima Raf., Fl. Tellur. 2:46. 1836 [1837].

Mesoligus Raf., Fl. Tellur. 2:44. 1836 [1837].

Aster sect. Conyzopsis Torr. & A. Gray, Fl. N. Amer. 2:162. 1841.

Aster subg. Conyzopsis (Torr. & A. Gray) A. Gray, Proc. Amer. Acad. Arts 16:99. 1880.

Brachyactis Ledeb., Fl. Ross. 2:495. 1845.

 

Fibrous-rooted, mostly herbaceous perennials 1–15(–18) dm tall, from a rhizome or short caudex, often producing stoloniform rhizomes, rarely (sect. Oxytripolium, sect. Conyzopsis) taprooted annuals. Leaves alternate, simple, variable in shape, linear to cordate, petiolate to sessile and clasping, 1–15 cm long, entire or toothed but not lobed or divided. Heads in cylindric or diffuse-paniculate inflorescences, sometimes somewhat corymboid; involucres narrowly campanulate to hemispheric, 3–10(–15) mm high; phyllaries in 3–7 graduate to subequal series, mostly with a whitish-indurated base and herbaceous apical area; receptacle without chaff, flat to slightly convex. Ray florets pistillate, fertile, the lamina prominent (reduced in sect. Conyzopsis), white to blue or purplish, coiling with maturity. Disc florets perfect, fertile, the corollas yellow, usually purplish at maturity, gradually ampliate, the lobes deltate to triangular, erect to spreading; style branches with lanceolate collecting appendages. Cypselae narrowly obovate, (1–)1.5–3.5(–4) mm long, flattened to varying degrees, (2–)3–5(–6) nerved, sparsely strigose to glabrous; pappus of numerous barbellate bristles in a single series or (only in sect. Conyzopsis) in 2 series. Base chromosome numbers, x=8, 7, 6, 5, 4. (Greek, symphysis, junction or seam, trichos, hair, the meaning obscure, but perhaps referring to a perceived basal connation or caducous tendency of the pappus bristles, perhaps possible in the European cultivar apparently studied by Nees.)

      Type species: Symphyotrichum unctuosum Nees (?= S. novi-belgii [L.] Nesom; see comments by Labrecque et Brouillet 1996, Brouillet and LaBrecque 1997).

      Symphyotrichum is primarily a North American genus of about 91 species; one species group of subg. Virgulus is primarily Mexican (Nesom 1989), and sect. Oxytripolium has radiated primarily in South America. Seven species are restricted to Mexico; at least seven are restricted to South America; all others are autochthonous in North America north of Mexico. Various species of Symphyotrichum are widely naturalized outside of the New World, especially in Europe (e.g., Hoffman 1996). Interbreeding among species cultivated for the cut-flower industry is so prevalent that a separate classification (a “cultonomy”) has been proposed in place of Latin binomials (Hetterscheid & Van Den Berg 1996).

      Species of Symphyotrichum have mostly been treated within Aster, but Nesom (1994) has presented a case for regarding the latter as a genus primarily restricted to the Old World, with Symphyotrichum by far the largest of the New World segregates. Symphyotrichum subg. Virgulus has previously been treated as the genus Virgulus (Semple & Brouillet 1980; Reveal & Keener 1981); Symphyotrichum sect. Conyzopsis has been treated as the genus Brachyactis by Jones (1989, 1992) and various floristicians. Xiang and Semple (1996) informally suggested that the monotypic Canadanthus and Ampelaster should be included as basal elements of a further expanded Symphyotrichum, although Semple et al. (1996) maintained the whole group as a portion of Aster.

      The recent realignment of generic boundaries (Nesom 1994) is based on morphology and cytology, especially achenial features and chromosome morphology, which indicate that New World Aster is only distantly related to Old World species and that many of the American species groups are phyletically coherent. Xiang and Semple (1996) and Semple et al. (1996) have maintained large groups of American species within Aster, based on cpDNA restriction site data indicating that the Old World generitype of Aster s. str. (A. amellus L.) is phyletically imbedded within one of the North American groups (Eurybia, as treated here). Nuclear ribosomal ITS data of Noyes and Rieseberg (1999), however, support Nesom’s hypothesis and place A. amellus and Old World relatives as closely related to other accepted genera of the Old World and Southern Hemisphere.

      Symphyotrichum has been divided into two major groups: (1) subg. Symphyotrichum (x=8, reduced to x=7 and x=6 and 5 in two sections), including sects. Symphyotrichum, Concinni, Cordifolii, Dumosi, and Occidentales (x=8), sect. Conyzopsis (x=7), and sect. Oxytripolium (x=6,5); (2) subg. Virgulus (x=5), including sects. Concolores, Patentes, Ericoidei, and Grandiflori. Additionally, sect. Ascendentes (x=13) comprises species and backcross populations of hybrid origin between sect. Occidentales and sect. Grandiflori (Jones 1977; Allen 1984, 1985, 1986; Allen & Chambers 1983; Allen et al. 1983; Dean & Chambers 1983; Allen & Eccleston 1998). An analogous amphiploid hybrid (x=13) has been reported from Mexico by Sundberg (1986) between sect. Oxytripolium (x=5) and sect. Dumosi (x=8) of subg. Symphyotrichum. An artificially synthesized backcross between this hybrid (x=13) and its oxytripolioid parent (x=5) was fertile and had a chromosome number of 2n=36.

      Molecular data of Xiang and Semple (1996) indicate that Aster pauciflorus Nutt. (x=9), treated here as the monotypic genus Almutaster, is closely related to the species of sect. Oxytripolium and may be better treated within Symphyotrichum. Complicating this interpretation is the absence of species of Psilactis (which see) from broadly based molecular analyses – Psilactis has recently been accepted as a distinct genus but apparently also is closely related to elements of Symphyotrichum including Almutaster.

      Two other North American species with x=9, Aster carolinianus Walt. and A. modestus Lindl., segregated as the monotypic genera Ampelaster and Canadanthus, respectively, by Nesom (1994), apparently evolved as isolated, basal elements of the Symphyotrichum complex, according to cpDNA data of Xiang and Semple (1996). Xiang and Semple, followed by Semple et al. (1996), suggest that these two species be incorporated within Symphyotrichum.

      Symphyotrichum sect. Conyzopsis (= Brachyactis) is a distinctive and discrete group of three species, two endemic to North America and one circumboreal. It was recently accepted at generic level by Jones (1989, 1992). Plants of this group are recognized by their base chromosome number of x=7, annual duration, evenly foliaceous and even-length phyllaries, pistillate florets with highly reduced lamina in a broad outer zone of 2–4 series, more numerous than the disc florets, and narrowly oblong, flattened, eglandular cypselae with a biseriate pappus of accrescent bristles. Several Aster overviews (including Nesom 1994) have suggested that the group is most closely related to S. spathulatum (Lindl.) Nesom (= Aster occidentalis (Nutt.) Torr. & A. Gray) and its close relatives. The molecular study by Xiang and Semple did not confirm this phyletic hypothesis but placed sect. Conyzopsis within the topologic bounds of Symphyotrichum. Himalayan and central Asian plants treated as species of Brachyactis probably constitute two separate undescribed genera and apparently are related to other Old World genera rather than to Brachyactis s. str. or any other New World taxa (see comments in Nesom 1994).

      Many taxonomic studies of species and species groups of Symphyotrichum (as Aster) have been published, these dealing primarily with chromosomal and morphological variation. Access to this body of literature can be gained from the broader references cited below.

 

references

 

Allen, G.A. 1984. Morphological and cytological variation in the western North American Aster occidentalis complex (Asteraceae). Syst. Bot. 9:175–191.

Allen, G.A. 1985. The hybrid origin of Aster ascendens (Asteraceae). Amer. J. Bot. 72:268–277.

Allen, G.A. 1986. Amphidiploid origin of two endemic races of Aster (Asteraceae) in southern California. Amer. J. Bot. 73:330–335.

Allen, G.A., M.L. Dean, and K.L. Chambers. 1983. Hybridization studies in the Aster occidentalis (Asteraceae) polyploid complex of western North America. Brittonia 35:353–361.

Allen, G.A. and C.L. Eccleston. 1998. Genetic resemblance of allotetraploid Aster ascendens to its diploid progenitors Aster falcatus and Aster occidentalis. Canad. J. Bot. 76:338-344.

Brouillet, L. and J. Labrecque. 1997. New combinations in Symphyotrichum (Syn. Aster, Asteraceae: Astereae) species from northeastern North America. Phytologia 82:137–141.

Cronquist, A. 1943. Revision of the western North American species of Aster centering about Aster foliaceus Lindl. Amer. Midl. Nat. 29:429–468.

Dean, M.L. and K.L. Chambers. 1983. Chromosome numbers and evolutionary patterns in the Aster occidentalis (Asteraceae) polyploid complex of western North America. Brittonia 35:189–196.

Hetterscheid, W.L.A. and R.G. Van Den Berg. 1996. Cultonomy of Aster L. Acta Bot. Neerl. 45:173-181.

Hoffman, M.H. 1996. Escaped and cultivated North American asters of Central Europe. Feddes Repert. 107:163-188.

Jones, A.G. 1977. New data on chromosome numbers in Aster section Heterophylli (Asteraceae) and their phylogenetic implications. Syst. Bot. 2:334–347.

Jones, A.G. 1980a. Classification of the New World species of Aster (Asteraceae). Brittonia 32:230–239.

Jones, A.G. 1980b. Data on chromosome numbers in Aster (Asteraceae), with comments on the status and relationships of certain North American species. Brittonia 32:240–261.

Jones, A.G. and D. Young. 1983. Generic concepts of Aster (Asteraceae): A comparison of cladistic, phenetic, and cytological approaches. Syst. Bot. 8:71–84.

Jones, A.G. 1989. Aster and Brachyactis in Illinois. Illinois Nat. Hist. Survey Bull. 34:139–194.

Jones, A.G. 1992. Aster and Brachyactis in Oklahoma. Sida, Bot. Miscell. 8:1–46.

Labrecque, J. et L. Brouillet. 1996. Biosystιmatique du complexe de l’Aster novi-belgii (Asteraceae: Astereae) au Quιbec. Canad. J. Bot. 74:162–188.

Nesom, G.L. 1989. A new species of Aster (Asteraceae: Astereae) from Mexico. Phytologia 67:342–345.

Nesom, G.L. 1994. Review of the taxonomy of Aster sensu lato (Asteraceae: Astereae), emphasizing the New World species. Phytologia 77:141–297.

Nesom, G.L. 1997. Taxonomic adjustments in North American Aster sensu latissimo (Asteraceae: Astereae). Phytologia 82:281–288.

Noyes, R.D. and L.H. Rieseberg. 1999. ITS sequence data support a single origin of North American Astereae (Asteraceae) and reflect deep geographic divisions in Aster s.l. Amer. J. Bot. 86:398–412.

Reveal, J.L. and C.S. Keener. 1981. Virgulus Raf. (1837), an earlier name for Lasallea Greene (1903) (Asteraceae). Taxon 30:648–651.

Semple, J.C. and L. Brouillet. 1980a. A synopsis of North American Asters: The subgenera, sections and subsections of Aster and Lasallea. Amer. J. Bot. 67:1010–1026.

Semple, J.C. and L. Brouillet. 1980b. Chromosome numbers and satellite chromosome morphology in Aster and Lasallea. Amer. J. Bot. 67:1027–1039.

Semple, J.C., J.G. Chmielewski, and C.C. Chinnappa. 1983. Chromosome number determinations in Aster L. (Compositae) with comments on cytogeography, phylogeny and chromosome morphology. Amer. J. Bot. 70:1432–1443.

Semple, J.C., S.B. Heard, and C.S. Xiang. 1996. The Asters of Ontario (Compositae: Astereae): Diplactis Raf., Oclemena E.L. Greene, Doellingeria Nees and Aster L. (including Canadanthus Nesom, Symphyotrichum Nees, and Virgulus Raf.). Rev. ed. Univ. of Waterloo Biol. Ser. 38:i–viii, 1–94.

Sundberg, S.D. 1986. The systematics of Aster subg. Oxytripolium (Compositae) and historically allied species. Ph.D. diss., Univ. of Texas, Austin.

Xiang, C. and J.C. Semple. 1996. Molecular systematic study of Aster s. lat. and related genera (Asteraceae: Astereae) based on chloroplast DNA restriction site analyses and mainly North American taxa. In D.J.N. Hind and H.J. Beentje (eds.). Compositae: Systematics. Vol. 1, pp. 393–423. Proc. Interntl. Compositae Conf., Kew, 1994.

 

79. TETRAMOLOPIUM Nees, Gen. Sp. Aster. 202. 1832.

 

Vittadinia sect. Tetramolopium A. Gray, Proc. Amer. Acad. Arts 5:119. 1861.

Luteidiscus St. John, Bot. Jahrb. 94:549. 1974.

 

Short-lived perennial shrubs or subshrubs, monoecious or gynomonoecious, caespitose, decumbent, procumbent, or erect, the stems 2.5–40(–200) cm tall, sympodially branched, with leaves on short internodes clustered near the tips, roughened below by persistent leaf bases, each terminated by a head or inflorescence, sometimes stipitate-glandular or glandular-punctate. Leaves alternate, simple, lanceolate to linear-oblanceolate or spatulate, 1–6.5 cm long, entire to dentate or shallowly lobed, sessile or petiolate, thin, succulent, or sclerophyllous. Heads radiate, solitary on bracteate peduncles or 6–50 and loosely corymboid; involucres cylindric, campanulate, hemispheric, or turbinate, 2–9 mm high; phyllaries lanceolate to linear-lanceolate, imbricate in 3–4 series; receptacles mostly flat, alveolate, without bracts. Ray florets 5–250, pistillate fertile, yellow or white. Disc florets perfect or functionally staminate, yellow or maroon, the limb gradually to abruptly opening above the tube, the lobes narrowly to broadly lanceolate, erect to spreading; style branches with lanceolate to deltate collecting appendages. Cypselae oblanceolate to obovoid, strongly flattened with prominently thickened margins, rarely fusiform-cylindric, 1–4.5 mm long, with 0–7 nerves on each face, glabrous, stipitate-glandular, or strigose, or glandular and strigose; pappus in 1 series (sect. Tetramolopium, most species of sect. Sandwicense) or 2 series of numerous barbellate bristles of unequal length. Base chromosome number, x=9. (Greek, tetra, four, lope, cloak or mantle, or lopos, peel or scale, the nature of the allusion to the plants unclear.)

Lectotype species (Pfeiffer 1874): Tetramolopium tenerrimum (Less.) Nees.

      A genus of 38 species –– 25 in the high uplands of New Guinea (Koster 1966; Van Royen 1983), 11 in Hawaiian Islands (Lowrey 1986), and one in the Cook Islands (more than 3000 km south of Hawaii) (Lowrey 1995). A Tetramolopium species was recently described from Queensland in northeastern Australia by Pedley (1993), who noted that it is closest to the New Guinean species T. bicolor Koster.

      Plants of Tetramolopium are recognized by the following features: short-lived diploid perennials, small shrubs or subshrubs with leaves clustered at the stem tips, heads solitary or loosely corymboid, yellow or white rays and yellow or maroon discs, functionally staminate disc florets (in sect. Tetramolopium and the New Guinean species) or fully bisexual (all other species), strongly flattened, beakless and neckless, usually facially nerved, often glandular cypselae, and a 1- or 2-seriate pappus of barbellate bristles. The Hawaiian species represent a diverse array of sexual expression, life form, and habitat (six of the species have formally recognized infraspecific variants), in contrast to those of New Guinea, which are largely monecious, caespitose, alpine shrublets.

      The species have been divided into three sections: sect. Tetramolopium, with 6 species in Hawaii; sect. Alpinum Lowrey, including all New Guinean taxa and the single Hawaiian species T. humile (A. Gray) Hillebr.; and sect. Sandwicense Lowrey, with 4 species in Hawaii. The Hawaiian species as a group are monophyletic, derived from the Asian stock, apparently by long-distance dispersal in the Pleistocene (Lowrey 1995). Tetramolopium humile is the phyletically basal Hawaiian species (Lowrey 1995), presumably having retained its primitive features. The Cook Islands plants are closely similar in morphology, anatomy, and sexual expression to species of sect. Tetramolopium and apparently were established through a secondary dispersal event, cypselae perhaps carried by migrating Pacific Golden Plover (see Lowrey 1995) early in the history of Hawaiian Tetramolopium. Cladistic relationships based on nuclear RFLP markers (Okada et al. 1997) and ITS sequences (Chan et al. 1995; Lowrey et al. 1997) are in essential agreement with the patterns based on morphological data, except that the position of the Cook Islands plants is equivocal.

      Low levels of genetic diversity occur within the Hawaiian species and high average genetic identities are found among them, based on isozyme analysis (Lowrey & Crawford 1985). All hybrids from interspecific crosses among nine Hawaiian species in three sections were fertile through the F2 generation (Lowrey 1986). These observations are consistent with a hypothesis of recent origin and rapid diversification.

      The interrelationships of Tetramolopium species and putative relatives within the Vittadinia group (sensu Nesom 1994) and subtribe Podocominae are currently in under detailed investigation by Dr. T.K. Lowrey and colleagues.

 

references

 

Chan, R., T. Lowrey, D. Natvig, and R. Whitkus. 1995. Phylogenetic analysis of internal transcribed spacer (ITS) sequences from nuclear ribosomal DNA of Hawaiian, Cook Island, and New Guinea Tetramolopium. Amer. J. Bot. [abstract] 82(6):118–119.

Koster, J.T. 1966. The Compositae of New Guinea I. Nova Guinea, Bot. 24:524–612.

Lowrey, T.K. 1986. A biosystematic revision of Hawaiian Tetramolopium (Compositae – Astereae). Allertonia 4:204–262.

Lowrey, T.K. 1995. Phylogeny, adaptive radiation, and biogeography of Hawaiian Tetramolopium (Asteraceae, Astereae). Pp. 195–220 in W.L. Wagner and V.A. Funk (eds.). Hawaiian Biogeography. Smithsonian Inst. Press, Washington, DC.

Lowrey, T.K. and D.J. Crawford. 1985. Allozyme divergence and evolution in Tetramolopium (Compositae: Astereae) in the Hawaiian Islands. Syst. Bot. 10:64–72.

Lowrey, T., R. Chan, D. Daniels, and R. Whitkus. 1995. Phylogenetic relationships and taxonomic status of Cook Islands Tetramolopium (Compositae) based on artificial hybridization and molecular evidence. Amer. J. Bot. [abstract] 82(6):147–148.

Lowrey, T.K., C. Quinn, R. Taylor, and J. De Nardi. 1997. Intergeneric relationships of Tetramolopium (Asteraceae) and Australian Astereae based on morphology, anatomy, and ITS sequences of nrDNA. Amer. J. Bot. [abstract] 84(6):21.

Nesom, G.L. 1994. Subtribal classification of the Astereae (Asteraceae). Phytologia 76:193–274.

Okada, M., R. Witkus, and T.K. Lowrey. 1997. Genetics of adaptive radiation in Hawaiian and Cook Islands species of Tetramolopium (Asteraceae: Astereae). I. Nuclear RFLP marker diversity. Amer. J. Bot. 84:1236–1246.

Pedley, L. 1993. Sigesbeckia fugax, a new species and Tetramolopium vagans, new species, new Astereae from Queensland. Austrobaileya 4:87–92.

Pfeiffer, L.K.G. 1873–1874. Nomenclator Botanicus. Vols. 1 and 2. Cassel [Vol. 2:1376. 1874].

Sherf, E.E. 1935. Revision of Tetramolopium, Lipochaeta, Dubautia, and Railliardia. Bishop Mus. Bull. 135:1–136.

St. John, H. 1974. Pacific plant studies 25: Luteidiscus, new genus (Compositae). Bot. Jarhb. 94:549–555.

Van Royen, P. 1983. Tetramolopium. The Alpine Flora of New Guinea. Vol. 4:33245–3311. J. Cramer, Vaduz, Liechtenstein.

Whitkus, R. 1998. Genetics of adaptive radiation in Hawaiian and Cook Islands species of Tetramolopium (Asteraceae). II. Genetic linkage map and its implications for interspecific breeding barriers. Genetics 150:1209–1216.

Whitkus, R., H. Doan, and T. Lowrey. 1996. Genetic control of female sterility in Hawaiian Tetramolopium (Asteraceae). Amer. J. Bot. [abstract] 83(6):100.

 

80. THUROVIA Rose, Contr. U.S. Natl. Herb. 3:321. 1895.

 

Annual or short-lived perennial herbs, the stems 6–45 cm tall, branched on the upper half, taprooted or the root spreading laterally in perennating forms. Leaves cauline, alternate, linear, 2–10(–15) mm long, ascending-appressed, gradually reduced upward. Heads solitary in the leaf axils, usually 10–20 per stem, sessile or subsessile and the inflorescence appearing spicate; involucres narrowly obconic, 3–4 mm high; phyllaries 5–9 in 2 series, the inner somewhat squarrose; receptacles without chaff. Ray florets absent. Disc florets 3, perfect, fertile, the corollas white or pale yellow, 2.3–2.8 mm high, with lanceolate, spreading-recurved lobes. Cypselae obconic, 0.9–1.7 mm long, subterete, densely and evenly white-sericeous with thick trichomes; pappus in 2 series of ca. 10, erose, apiculate scales as long as the corollas. Base chromosome number, x=5. (For naturalist and plant collector Frederick William Thurow, born 1852, of Hockley, Texas, near Houston.)

      Type species: Thurovia triflora Rose.

      A monotypic genus endemic to a few counties on the Gulf coastal plain of southeastern Texas. The single species was treated by Lane (1985) within Gutierrezia but indicated by data of Suh and Simpson (1991) to be the sister group of Amphiachyris. Thurovia is distinctive in its spicate inflorescence of tiny, axillary, few-flowered, discoid heads with white corollas, densely sericeous cypselae, and scaly pappus.

 

references

 

Lane, M.L. 1982. Generic limits of Xanthocephalum, Gutierrezia, Amphiachyris, Gymnosperma, Greenella, and Thurovia (Compositae: Astereae). Syst. Bot. 7:405–416.

Lane, M.A. 1985. Taxonomy of Gutierrezia (Compositae: Astereae) in North America. Syst. Bot. 10:7–28.

Rose, J.N. 1895. Thurovia, a new genus of Compositae. Contr. U.S. Natl. Herb. 3:320–322.

Suh, Y. and B.B. Simpson. 1991. Phylogenetic analysis of chloroplast DNA in North American Gutierrezia and related genera (Asteraceae: Astereae). Syst. Bot. 15:660–670.

 

81. TOMENTAURUM Nesom, Phytologia 71:129. 1991.

 

Perennial herbs with erect, unbranched stems 12–25 cm tall, from slender, lignescent rhizomes, these producing long, caudex-like branches with scale leaves; stems, leaves, and phyllaries densely glandular with sessile- or short-stipitate, orange-headed hairs, the stems and leaves tomentose with very long, uniseriate, few-celled, minutely filiform white hairs from equally small bases, completely lacking thicker uniseriate trichomes. Leaves in a basal rosette or low-cauline, oblanceolate-obovate, 2–4 cm long, 3–9 mm wide, entire, the cauline subclasping. Heads solitary on long, scapose peduncles, apparently nodding in bud; involucres hemispheric, 10–13 mm high; phyllaries narrowly ovate-lanceolate, strongly graduated in 5–6 series, the margins purplish, with a prominent, hyaline flange, the outer herbaceous, the middle strongly keeled, herbaceous only at the apex; receptacles shallow convex, barely foveolate. Ray florets 16–21, pistillate, fertile, the corollas yellow, tightly coiling after anthesis. Disc florets perfect, fertile; style branches with linear-lanceolate collecting appendages. Cypselae linear-oblong, 4.5–5.5 mm long, strongly compressed, densely white-sericeous, with 7–9 thin nerves on each side; pappus of 45–60 white, barbellate bristles in several series, with a few, inconspicuous setae or very slightly widened bristles 0.5–1.5 mm long. Chromosome number unknown, predicted x=9. (Latin, tomentum, closely woolly hairs, aurum, gold, in reference to the vestiture.)

      Type species: Tomentaurum niveum (S. Wats.) Nesom.

      A monotypic genus of subtribe Chrysopsidinae (Nesom 1991a, 1994) endemic to west-central to south-central Chihuahua, Mexico. Tomentaurum is distinguished by a combination of features: rhizomatous habit, stipitate-glandular herbage, persistent basal leaves, obovate-oblanceolate, dense and closely white-tomentose, keeled phyllaries, large, solitary heads on long scapes, yellow, coiling lamina, disc corollas very long, crystal-bearing, with linear-lanceolate style appendages, cypselae narrowly oblong and strongly compressed, with numerous, whitish, superficial nerves and an asymmetric carpopodium, and a double pappus. The species of Osbertia are somewhat similar to Tomentaurum in habit, but the latter is hypothesized to be more closely related to Pityopsis and Croptilon (Nesom 1991b), based on the vestiture of filiform, thin-based trichomes.

 

references

 

Nesom, G.L. 1991a. Tomentaurum (Asteraceae: Astereae), a new genus of goldenaster from Chihuahua, Mexico. Phytologia 71:128–131.

Nesom, G.L. 1991b. A phylogenetic hypothesis for the goldenasters (Asteraceae: Astereae). Phytologia 71:136–151.

Nesom, G.L. 1994. Subtribal classification of the Astereae (Asteraceae). Phytologia 76:193–274.

 

82. TONESTUS A. Nelson, Bot. Gaz. 37:262. 1904.

 

Haplopappus sect. Tonestus (A. Nels.) H.M. Hall, Carnegie Inst. Wash. 389:34. 1928.

 

Perennial herbs 3–20 cm tall, arising from thick, woody caudex branches or less commonly with a distinct taproot, from a system of slender rhizomes in T. lyallii, the stems, leaves, and phyllaries densely pilose-glandular with long, vitreous, biseriate, gland-tipped hairs, eglandular in one species. Leaves 3-veined from the base, obovate, 1–8 cm long, the margins toothed-spinulose or entire, subclasping but not auriculate, often persistent in a rosette but the stems leafy, the upper cauline grading into phyllaries. Heads discoid or radiate, sometimes few and loosely corymboid but most commonly solitary; involucres turbinate to hemispheric or campanulate, 5–18 mm high; phyllaries in 3–4 subequal series, at least the outer foliaceous. Ray florets absent or present and pistillate, fertile, yellow or white. Disc florets perfect, fertile, the corollas narrowly tubular; style branches with lanceolate collecting appendages. Cypselae narrowly oblong to slightly fusiform, 2–5 mm long, terete to somewhat compressed, 5-nerved, 5–8 nerved, or 8–12 nerved (see below), glabrous to strigose; pappus of barbellate, apically attenuate bristles in (1–)2 series, with a short outer series in one species. Base chromosome number, x=9. (An anagram of Stenotus, alluding to a resemblance.)

      Type species: Tonestus lyallii (A. Gray) A. Nelson.

      A genus of eight species, recently broadened by the addition of species from Haplopappus (Hall 1928; Anderson 1980; Tiehm & Shultz 1985; Nesom & Morgan 1990) and from Aster s. lat. (Nesom 1991). Rather than in Tonestus (fide Nesom & Morgan 1990), Haplopappus microcephalus Cronquist is better placed in or near Chrysothamnus. Plants of Tonestus occur in crevices, talus slopes, and other rocky places in the western United States and southwestern Canada. The genus is recognized by its low habit from a branching caudex, vestiture of long, stipitate-glandular hairs, persistent basal leaves and cauline leaves relatively unreduced to immediately below the heads, heads solitary or few and loosely corymboid, subequal phyllaries, the outer usually foliaceous, 1-seriate pappus, and base chromosome number of x=9. Tonestus, however, is perhaps among the most morphologically heterogeneous North American genera of Astereae (especially for its relatively few species), varying in most of the features that might be used in a less equivocal definition: habit, vestiture, leaf margins, degree of cauline leaf development, the nature of the inflorescence, phyllary morphology, style appendage morphology, ray color, and cypsela and pappus morphology. Still, the species of Tonestus appear to be overlapping in their patterns of variability, and it is difficult to discern discrete subgroups. The species appear to be interrelated, but the possibility remains that the genus, as considered here, is not monophyletic.

 

references

 

Anderson, L.C. 1980. Haplopappus alpinus (Asteraceae): a new species from Nevada. Great Basin Nat. 40:73–77.

Hall, H.M. 1928. The genus Haplopappus – A phylogenetic study in the Compositae. Section 8. Tonestus. Carnegie Inst. Washington Publ. No. 389:34, 177–187.

Nelson, A. 1904. Contributions from the Rocky Mountain Herbarium. V. Bot. Gaz. 37:260–279.

Nesom, G.L. and D.R. Morgan. 1990. Reinstatement of Tonestus (Asteraceae: Astereae). Phytologia 68:174–180.

Nesom, G.L. 1991. Transfer of Aster kingii to Tonestus (Asteraceae: Astereae). Phytologia 71:122–127.

Tiehm, A. and L.M. Shultz. 1985. A new Haplopappus (Asteraceae: Astereae) from Nevada. Brittonia 37:165–168.

 

83. TOWNSENDIA Hook., Fl. Bor.-Amer. 2:16. 1834.

 

Annual, biennial, or perennial herbs, the stems 0.5–3 dm tall, taprooted, often with a branching caudex, stoloniferous and fibrous-rooted in one species, mostly strigose with short, white hairs. Leaves alternate, spatulate to linear, 1–13 cm long, entire or rarely toothed, basal or basal and cauline. Heads solitary, sessile or pedunculate; involucres hemispheric to campanulate, 5–20 mm high; phyllaries imbricate in 2–7 series, usually with broad, hyaline-ciliate margins; receptacle convex, rarely conical. Ray florets pistillate, fertile, the corollas white to bluish or pinkish above, yellow in one species, usually with a well-defined lavender to pink midstripe beneath. Disc florets perfect, fertile, the corollas yellow, with deltate, erect or incurved lobes; style branches with triangular-lanceolate collecting appendages. Cypselae oblanceolate to obovate, 2.5–6.5 mm long, laterally compressed, 2(–3)-ribbed, the surfaces smooth or papillate, glabrate or usually pubescent with duplex hairs with glochidiate, bifurcate, or entire apices; pappus uniseriate, of barbellate bristles or very short bristles and squamellae less than 1.5 mm long, ray pappus similar or variously shortened. Base chromosome number, x=9. (For amateur botanist of West Chester, Pennsylvania, David Townsend, 1787–1858.)

      Type species: Townsendia exscapa (Richards.) Porter.

      A genus of 26 species, including a number of recently described narrowly endemic ones (Beaman 1954; Welsh & Reveal 1968; Clark & Dorn 1979; Shultz & Holmgren 1980; Dorn 1992; Lowrey & Knight 1994). All but two of the Townsendia species are restricted to North America north of Mexico: T. exscapa barely crosses southward into Mexico, while T. mexicana A. Gray is strictly Mexican. Polyploidy, hybridization, and agamospermy (in the polyploids) complicate the taxonomic patterns. The genus is recognized by relatively large heads, broad, thin phyllaries with hyaline margins, mostly white or bluish rays, strongly compressed cypselae with two, thick, lateral ribs, the surfaces smooth or papillate, often with glochidiate hairs, and base chromosome number of x=9. Astranthium, which is similar and closely related to Townsendia, has epappose cypselae with inconspicuous nerves and consistently papillate surfaces and a base chromosome number of x=3.

 

references

 

Beaman, J.H. 1954. Chromosome numbers, apomixis, and intraspecific hybridization in the genus Townsendia. Madrono 12:169–180.

Beaman, J.H. 1957. The systematics and evolution of Townsendia (Compositae). Contr. Gray Herb. 183: 1–151.

Dorn, R.D. 1974. Nomenclatural notes on Townsendia. Madrono 22:401.

Clark, T.W. and R.D. Dorn. 1979. Rare and endangered vascular plants and vertebrates of Wyoming. Published by the authors.

Dorn, R.D. 1992. Townsendia microcephala (Asteraceae: Astereae): A new species from Wyoming. Madrono 39:189–192.

Larsen, E.L. 1927. A revision of the genus Townsendia. Ann. Missouri Bot. Gard. 14:1–47.

Lowrey, T.K. and P.J. Knight. 1994. Townsendia gypsophila (Compositae: Astereae): A new species from northern New Mexico. Brittonia 46:194–199.

Reveal, J.L. 1970. A revision of the Utah species of Townsendia (Compositae). Great Basin Nat. 30:23–52.

Schultz, L.M. and A.H. Holmgren. 1980. A new species of Townsendia (Asteraceae) from northern Arizona. Brittonia 32:144–147.

Welsh, S.L. and J.L. Reveal. 1968. A new species of Townsendia (Compositae) from Utah. Brittonia 20:375–377.

 

84. TRACYINA Blake, Madrono 4:74. 1937.

 

Annual, taprooted herbs 15–30 cm tall, glabrous or loosely pilose below the heads, the stem unbranched until the inflorescence or with a few, subterminal, spreading-ascending, lateral branches, sometimes with several branches from the base. Leaves cauline, ascending to appressed, alternate, linear to linear-oblanceolate, 0.5–2cm long, entire, the margins ciliate. Heads terminal, solitary; involucres cylindric to broadly ovoid, 6–7 mm long; phyllaries in 3–4 imbricate series, linear-lanceolate with narrow, hyaline margins, individually deciduous; receptacles without chaff. Ray florets 12–20, pistillate, fertile, the lamina erect, filiform, 4–5 mm long, pale or greenish yellow, red-tinged. Disc florets 15–25, the corollas filiform-tubular, greenish-yellow; style branches with linear-lanceolate collecting appendages. Cypselae narrowly cylindric to linear-fusiform, 5–5.5 mm long, 5-nerved, narrowed to a slender, strigose beak ca. Ό the cypsela length, strigose-hispid with short hairs; pappus of numerous, fragile, barbellate bristles in 1–2 series. Base chromosome number, x=9. (For northwestern California botanist Joseph P. Tracy, 1879–1953.)

      Type species: Tracyina rostrata Blake.

      A monotypic genus endemic to grassy slopes of the North Coast Ranges in Humboldt and Lake counties, California, recognized by its slenderly taprooted annual habit, narrow, ascending leaves, few heads with inconspicuous rays, and slender, short-beaked cypselae with a pappus of barbellate bristles. Tracyina is closely related to Rigiopappus, another monotypic genus of the same geographic region, and to Pentachaeta. Artificially hybrids between Tracyina and Rigiopappus were produced by Ornduff and Bohm (1976), who observed that the two “should be placed side by side in Astereae” – confirming similar earlier views of Blake (1937) and Robinson and Brettell (1973) – and that significant morphological differences support their treatment as distinct monotypic genera.

 

references

 

Blake, S.F. 1937. Tracyina, a new genus of Asteraceae from northern California. Madrono 4:73–77.

Ornduff, R. and B.A. Bohm. 1975. Relationships of Tracyina and Rigiopappus. Madrono 23:53–55.

Robinson, H. and R.D. Brettell. 1973. Tribal revisions in the Asteraceae. V. The relationship of Rigiopappus. Phytologia 26:69–70.

 

85. TRIPOLIUM Nees, Gen. Spec. Aster. 152. 1832.

 

Aster sect. Tripolium (Nees) Benth. in Benth. & J.D. Hook., Gen. Pl. 2:273. 1873.

 

Biennial to short-lived perennial, glabrous herbs, the stems erect, 1.5–8(–12) dm tall, branching, from a short, fibrous-rooted rhizome or caudex. Leaves thick, nearly succulent, the basal oblanceolate-spatulate, 4–25 cm long, usually with 3 distinct parallel nerves, the blades entire or minutely denticulate, petiole Ό as long as the blade, the cauline narrowly lanceolate or oblanceolate, epetiolate, clasping or non-clasping, continuing to the inflorescence. Heads usually 5–20 in terminal, loosely corymboid clusters, these grouped on branching plants; involucres turbinate, 6–8 mm high; phyllaries in (1–)2–3(–4) graduate series, evenly thin-herbaceous, lanceolate to oblong, with 3–5 parallel veins, obtuse to rounded. Ray florets 10–30, bright blue to purple, sometimes white and commonly drying white, sometimes absent and the heads discoid. Disc florets tubular-funnelform, the lobes lanceolate; style branches with ovate-triangular collecting appendages. Cypselae narrowly obovate to obovate, 2–3.5(–4.5) mm long, strongly flattened, with a pair of narrow but thickened marginal ribs, the surfaces strigose and sometimes sessile-glandular; pappus of 1–2 subequal series of barbellate bristles, strongly accrescent after anthesis, elongating to 11–12 mm, rarely shortened to 0.5 mm, sometimes basally caducous. Base chromosome number, x=9. (Greek, tripolion, leadwort, perhaps referring to the dull gray color sometimes seen in dried plants; Greek, polios, gray; or alluding to “tripolium,” the common name for some species of Limonium? Nees adopted the Linnaean epithet for the species in Aster as the generic name.)

      Type species: Tripolium pannonicum (Jacq.) Dobrocz. (= Aster tripolium L. = Tripolium vulgare Nees). The species was recently lectotypified (Jarvis and Turland 1998).

      A monotypic Eurasian genus that occurs in sandy shores, brackish marshes, and other saline habitats of sea coasts and around inland salt lakes in its native range. The species has mostly commonly been treated within Aster, but the corymboid inflorescence, broad and parallel-veined phyllaries, and obovate, flattened and 2-nerved, glandular cypselae suggest that Tripolium is closely related to the Old World genera Crinitaria Cass. (= Linosyris Cass.) and Galatella Cass., which also have been treated within Aster s. lat. (Nesom 1994). Sundberg (1976) also observed that Tripolium is most closely similar to other European species within Aster s. lat.

      Numerous species have been transferred to Tripolium or described within the genus. For the most part, these are now regarded as species of Symphyotrichum sect. Oxytripolium; others such species are in Symphyotrichum sect. Conyzopsis (= Brachyactis) and sect. Occidentales and in the North American genera Almutaster and Eurybia.

      Tripolium s. str. occurs from northern Europe southward to Italy and North Africa (Algeria), from there to Turkey, northern Iran, and the Caucasas region, and then scattered eastward across Asia to the Pacific from central China (but not Taiwan or Okinawa), Japan, and Korea northward to Manchuria and Siberia (see map in Wagenitz 1979). Two subspecies are generally recognized within T. pannonicum (Holub 1973; Merxmuller et al. 1976), although they apparently are subject to varying morphological and geographic interpretation: subsp. maritimum Holub, with monomorphic cypselae, ray florets often absent, occurs along the coasts of northern and and western Europe; subsp. pannonicum, with outer cypselae shorter and thicker and ray florets always present, occurs in south, central, and eastern Europe and presumably eastward to the Pacific. Grierson (1975) describes an Armenian plant that does not fit either established varietal category.

      In North America, Tripolium has been recorded in Pennsylvania and New York. Plants were collected on “ballast” in Philadelphia as waifs (23 Sep 1877, Parker s.n. US!; Aug 1878, Martindale s.n. US!), which were noted in Rhoads and Klein (1993) as the basis for recording its occurrence in Pennsylvania. It is noted by Mitchell and Tucker (1997) to be a “non-persistent species” in New York, not currently known from the wild.

 

references

 

Chakraborty, R. and J. Bogemans. 1997. Determination of relatedness of different ecotypes of Aster tripolium germplasm by RAPD analysis. Belg. J. Bot. 129:161.

Clapham, A.R, W.H. Pearsall, and P.W. Richards. 1942. Biological flora of the British Isles. Aster tripolium L. J. Ecol. 30:385–395.

Grierson, A.J.C. 1975. Astereae. Fl. Turkey East Aegean Islands 5:116–136.

Holub, J. 1973. New names in Phanerogamae 2. Folia Geobot. Phytotax. 8(2):155–179.

Huiskes, A.H.L. 1992. Cultivation of sea aster (Aster tripolium L.) in the province of Zeeland, The Netherlands. Mededel. Fac. Landbouw. Rijksuniv. Gent 57 (4 Part A–B):2181–2189.

Huiskes, A.H.L., J. Van Soelen, and M.M. Markusse. 1991. Differentiation within Aster tripolium L. from tidal and non-tidal habitats. Aquatic Bot. 39:35–44.

Jarvis, C.E. and N.J. Turland (eds.). 1998. Typification of Linnaean specific and varietal names in the Compositae (Asteraceae). Taxon 47:347–370.

Merxmuller, H., A. Schreiber, and P.F. Yeo. 1976. Aster. Flora Europaea 4:112–116.

Mitchell, R.S. and G.C. Tucker. 1997. Revised checklist of New York State plants. New York State Mus. Bull. 490. The State Education Dept., Albany, NY.

Nesom, G.L. 1994. Review of the taxonomy of Aster sensu lato (Asteraceae: Astereae), emphasizing the New World species. Phytologia 77:141–297.

Piotrowska, H. 1988 (1989). Materials for knowledge of the rare and endangered species of Poland 1. Aster tripolium L. Fragm. Fl. Geobot. (Wroclaw) 33:290–299.

Rechinger, K.H. 1982. Aster. Flora Iranica 154:4–6.

Rhoads, A.F. and W.M. Klein, Jr. 1993. The vascular flora of Pennsylvania: Annotated checklist and atlas. Amer. Philosophical Soc., Philadelphia, Penn.

Sterk, A.A. and D.O. Wijnands. 1970. On the variation in the flower heads of Aster tripolium L. in the Netherlands. Acta Bot. Neerl. 19:436–444.

Sundberg, S.D. 1986. The systematics of Aster subg. Oxytripolium (Compositae) and historically allied species. Ph.D. diss., Univ. of Texas, Austin.

Wagenitz, G. 1979. Aster. Illustrierte Flora von Mittel-europa. Band 6(4), Compositae 1:35–71.

Wagenvoort, W.A., J.G. Van De Vooren, and W.A. Brandenburg. 1989. Plant domestication and the development of sea starwort (Aster tripolium L.) as a new vegetable crop. Acta Horticult. (Wageningen) 242:115–122.

 

86. VANCLEVEA Greene, Pittonia 4:50. 1899.

 

Shrubs 4–10 dm tall, glabrous, heavily glutinous, the older stems with shedding epidermis or dull white bark, often with axillary fascicles of small leaves. Leaves alternate, linear-lanceolate, entire, rigid, spreading to falcate-recurved, mostly 3–4 cm long. Heads solitary or 2–5 in an open cyme, discoid; involucres broadly turbinate, 10–13 mm high; phyllaries narrowly elliptic-lanceolate, apically attenuate, in 3–5 strongly graduated series, the inner sometimes slightly squarrose. Disc corollas tubular, yellow, 7–8.5 mm long, the lobes deltate, erect; style branches with narrowly triangular-lanceolate collecting appendages. Cypselae narrowly cylindric, 4–5 mm long, subterete, ca. 5–8-nerved, heavily glutinous, sparsely strigose; pappus of (12–)15–18 flattened, paleaceous awns 2.5–3 mm long, often longer than the involucre at maturity. Base chromosome number, x=9. (For John W. Van Cleve of Dayton, Ohio, died 1860 or 1861, original member of the American Association for the Advancement of Science; “a letter in Torrey correspondence shows him as an enthusiastic and critical botanist.” – Barnhardt 1965)

      Type species: Vanclevea stylosa (Eastw.) Greene.

      A monotypic genus restricted to southeastern Utah and adjacent northern Arizona. The species was originally described within Grindelia (Eastwood 1896), but it is similar in many respects to Chrysothamnus, Hesperodoria, Petradoria, and Stenotus and apparently closely related to them (Anderson & Weberg 1974; Nesom 1991). Vanclevea is distinct in its shrubby habit, rigid, arcuate, viscid, and 3-nerved leaves, large heads nearly solitary or in a open cyme, and pappus of numerous paleaceous awns. In contrast to other recent studies, Lane and Li (1993) reported the chromosome number as 2n=12 and noted that morphological and molecular features suggest that the species belongs in the Machaerantherinae, but this apparently was based in part on misidentification of their voucher material (Nesom 1994, 1997).

 

references

 

Anderson, L.C. and P.S. Weberg. 1974. The anatomy and taxonomy of Vanclevea (Asteraceae). Great Basin Nat. 34:151–160.

Barnhardt, J.H. 1965. Biographical notes upon botanists. G.K. Hall, Boston, Mass.

Eastwood, A. 1896. Report on a collection of plants from San Juan County, in southern Utah. Proc. Calif. Acad. Sci. 2, 6:270–328.

Greene, E.L. 1899. Neglected generic types. Pittonia 4:45–51.

Lane, M.A. and J. Li. 1993. Documented chromosome numbers 1993:1. Chromosome number reports in Compositae with emphasis on tribe Astereae of the southwestern United States and Mexico. Sida 15:539–546.

Nesom, G.L. 1991. Redefinition of Hesperodoria (Asteraceae: Astereae) and the segregation of Columbiadoria, a new monotypic genus from the western United States. Phytologia 71:244–251.

Nesom, G.L. 1994. Subtribal classification of the Astereae (Asteraceae). Phytologia 76:193–274.

Nesom, G.L. 1997. Vanclevea (Asteraceae: Astereae): n=9 confirmed. Phytologia 82:130–133.

 

87. WESTONIELLA Cuatr., Phytologia 35:472. 1977.

 

Erect shrubs (in 3 species) with simple or branched stems 40–150 cm high to densely or loosely matted, prostrate, ascending, sometimes caespitose-pulvinate subshrubs up to 20 cm high, the branches densely imbricate-leafy, glabrous to white-woolly, sometimes sessile-glandular. Leaves alternate, linear-acicular to narrowly elliptic, 4–35 mm long, sessile, rigid, with revolute margins, entire, minutely and widely serrate, or with 3(–5) apical, finger-like lobes, sometimes apiculate, glabrous or arachnoid above, densely tomentose beneath. Heads in terminal, corymboid-glomerate panicles, or solitary, terminal, subsessile to short-pedicellate; involucres campanulate, 5–8 mm high; phyllaries in 4–5 subequal series, glabrous to white-woolly; receptacles slightly convex, alveolate, without chaff. Outer florets pistillate, in 2–4 series, filiform-tubular or slightly inflated distally, white to pink, reddish, or purple, minutely 5-toothed and contracted at the apex, erect or turned outward; style branches of typical morphology for Astereaean ray florets (continuous stigmatic lines, without sweeping hairs), slightly to well-exserted from the corollas. Disc florets functionally staminate, the ovaries sterile, tubular and regular, purple to reddish, usually darker than the pistillate florets, with 5, erect, triangular to deltate lobes; style branches linear, without stigmatic lines or clearly delimited collecting appendages. Cypselae obovate, 1.5–2.5 mm long, strongly flattened, with 2 lateral nerves and sometimes an additional, thinner nerve on each face, sparsely strigose to densely sericeous, usually sessile-glandular near the apex; pappus a single series of subequal barbellate bristles as long as the corollas. Base chromosome number unknown, predicted x=9. (For Dr. Arthur S. Weston, botanist/ecologist and student of the Costa Rican paramos, who collected all six of the species in 1966, 1969, 1976, and 1979.)

      Type species: Westoniella chirripoensis Cuatr.

      A genus of six species, five of which are endemic to the high elevation paramos of Costa Rica, with the sixth endemic to a closely adjacent region of Panama. The genus and all its species have been described by Cuatrecasas (1977, 1982), but the genus needs a detailed review for clarification of species delimitations. The plants are characterized by their high elevation habitats, low habit, narrow, rigid, revolute leaves densely imbricate on the stems, often woolly vestiture, discoid or disciform heads with functionally staminate disc florets and tubular ray florets, and flattened, obovate, glandular cypselae with a single series of pappus bristles. The relationship of Westoniella has been postulated to lie with a group of genera with similar geography and a similarly reduced habit (Laestadia, Flosmutisia Cuatr., and Floscaldasia Cuatr.), these placed in the subtribe Hinterhuberinae (Nesom 1993). Laestadia has a similar habit and similarly modified ray florets, but its cypselae are multinerved, nearly terete, and lack a pappus. The apparent widespread occurrence of morphological convergence in the tribe, however, makes such hypotheses of relationship speculative.

 

references

 

Cuatrecasas, J. 1977. Westoniella, a new genus of the Astereae from the Costa Rica paramos. Phytologia 35:471–487.

Cuatrecasas, J. 1982. Miscellaneous notes on Neotropical flora, XV. New taxa in the Astereae. Phytologia 52:166–177.

Nesom, G.L. 1993. Floscaldasia (Asteraceae: Astereae): First record from Ecuador and comments on its classification. Phytologia 75:366–368.

 

88. XANTHISMA DC., Prodr. 5:95. 1836.

 

Centauridium Torr. & A. Gray, Fl. N. Amer. 2:246. 1842.

 

Taprooted annual herbs, the stems often white, hispidulous, 2–10 dm tall, simple or with a few rigidly ascending branches from the lower half. Leaves mostly glabrous, alternate, the basal ovate to obovate, spinulose-toothed or -pinnatifid, less commonly entire, usually deciduous by flowering, the cauline mostly oblong-oblanceolate, becoming entire and linear upwards. Heads solitary at the ends of the upper branches; involucres hemispheric to campanulate or turbinate, 5–10 mm high; phyllaries in 3–4 graduate series, the upper portion green-herbaceous with a white rim, whitish below, the upper (green) portion broadly lanceolate, above a short, oblong, lower (white) portion, the outermost grading into the peduncular bracts; receptacles with persistent, narrowly triangular, chaffy bracts. Ray florets pistillate, fertile, 10–30, the yellow, sometimes drying with a purple tinge. Disc florets perfect, fertile, gradually ampliate with deltate, erect lobes; style branches with lanceolate collecting appendages. Cypselae dimorphic, stiffly strigulose: ray cypselae 3-angled, curved, pappus ca. 2–3 series of bristly-margined, awn-like scales of variable length, 3–3.5 mm long; disc cypselae obovate, shorter, and less angular, pappus scales of 2 distinct lengths, the inner to 6 mm long, the outer ca. half as long. Base chromosome number, n=4 pairs. (Greek, xanthos, yellow, -ismos, denoting condition or quality, for the bright yellow florets.)

      Type species: Xanthisma texanum DC.

      A monotypic genus distributed primarily in Texas and Oklahoma, reaching into New Mexico and Kansas and southward into the Rio Grande valley, possibly into Mexico, recognized by its solitary, yellow-rayed heads, distinctive phyllaries, chaffy receptacle, and dimorphic cypselae with a scaly pappus. Semple (1974a) recognized 2 subspecies within Xanthisma texanum distinguished primarily by involucral bract morphology: the northern subsp. drummondii (Torr. & A. Gray) Semple (= var. drummondii [Torr. & A. Gray] A. Gray) and the more southern subsp. texanum. Within subsp. texanum, two intergrading and geographically congruent varieties were recognized by Semple. Phylogenetic analyses from chloroplast DNA and nuclear ribosomal DNA (ITS) data suggest that Xanthisma and Xylorhiza may be the closest relatives of sections Blepharodon and Sideranthus of Machaeranthera (Morgan 1997).

      One or two B-chromosomes commonly are present in plants of Xanthisma texanum, but their geographic occurrence is random and plants with B-chromosomes are not morphologically distinguishable from those without them (Semple 1974b). Populational frequencies of these chromosomes vary over time (Semple 1989) and apparently do not affect morphological or ecological traits or pollen viability (Semple & Chmielewski 1989).

 

references

 

Morgan, D.R. 1997. Reticulate evolution in Machaeranthera (Asteraceae). Syst. Bot. 22:599–615.

Semple, J.C. 1974a. The phytogeography and systematics of Xanthisma texanum DC. (Asteraceae): Proper usage of infraspecific categories. Rhodora 76:1–19.

Semple, J.C. 1974b. The geographical distribution of B-chromosomes of Xanthisma texanum DC. (Asteraceae). I. Survey of the range. Amer. J. Bot. 61:995–1001.

Semple, J.C. 1976. The cytogenetics of Xanthisma texanum DC. (Asteraceae) and its B-chromosomes. Amer. J. Bot. 63:388–398.

Semple, J.C. 1989. Geographical distribution of B chromosomes of Xanthisma texanum (Compositae: Astereae). II. Local variation within and between populations and frequency variation through time. Amer. J. Bot. 76:769–776.

Semple, J.C. and J.G. Chmielewski. 1989. Studies on the effects, or lack thereof, of B chromosomes on the morphology and pollen viability in wild and cultivated plants of Xanthisma texanum (Compositae: Astereae). Canad. J. Bot. 67:1157–1160.

 

89. XANTHOCEPHALUM Willd., Ges. Naturfr. Freunde Berlin Mag. 1:140. 1807.

 

Xanthocoma Kunth in H.B.K, Nov. Gen. Sp. 4:310. 1820.

Grindeliopsis Schultz-Bip., Bonplandia 6:356. 1858.

Gunthera Regel, Gartenflora 7:44. 1858.

 

Annual or perennial herbs, taprooted or rhizomatous, erect or one species prostrate, 0.2–20 dm tall, glandular or glutinous or both. Leaves alternate, oblanceolate, 1.5–10 cm long, sessile, entire or spinulose-toothed, sometimes decurrent. Heads solitary or in loose corymbs; involucres hemispheric to campanulate, 3–7 mm high; phyllaries white-indurate basally, green above, in 2–4 graduate series; receptacles shallowly alveolate to naked except for raised points of cypsela attachment. Ray florets pistillate, fertile, 14–62, yellow to orange-yellow, absent in one species. Disc florets perfect, fertile, the tube abruptly expanded into the throat; style branches with deltate collecting appendages. Cypselae thick-walled, without prominent ribs, turgid, compressed with rounded edges to nearly terete or 4–6-sided, glabrous to very slightly strigillose; pappus absent or a low crown of awn-like scales or a lacerate corona, very rarely short bristles, usually shorter in ray. Base chromosome number, x=6. (Greek, xanthos, yellow, kephale, head.)

      Type species: Xanthocephalum centauroides Willd. ex Kunth.

      A genus of six species, all primarily centered in Mexico, mostly occurring in habitats that are at least intermittently wet. Xanthocephalum gymnospermoides (A. Gray) Benth. ranges into Texas and Arizona. The definition of Xanthocephalum was clarified by Lane (1982, 1983) with the transferral to Gutierrezia of a number of taxa traditionally considered Xanthocephalum. The genus is distinguished from Gutierrezia by its glabrous, foveolate receptacles, abruptly ampliate disc corollas, deltate style appendages, obpyramidal, glabrous cypselae with pappus coroniform, of basally fused scales or essentially lacking, and base chromosome number of x=6. Naturally occurring hybrids have been reported between Xanthocephalum humile (Kunth) Benth. and Isocoma veneta (Kunth) Greene (Hartman & Lane 1991).

 

references

 

Hartman, R.L. and M.A. Lane. 1991. A natural intergeneric hybrid in the x = 6 group of the Astereae (Asteraceae). Sida 14:321–329.

Lane, M.A. 1982. Generic limits of Xanthocephalum, Gutierrezia, Amphiachyris, Gymnosperma, Greenella, and Thurovia (Compositae: Astereae). Syst. Bot. 7:405–416.

Lane, M.A. 1983. Taxonomy of Xanthocephalum (Compositae: Astereae). Syst. Bot. 8:305–316.

Nesom, G.L. 1989. Comments on the annual species of Xanthocephalum (Compositae: Astereae) with a new combination. Phytologia 66:482–487.

Solbrig, O.T. 1961. Synopsis of the genus Xanthocephalum (Compositae). Rhodora 63:151–164.

 

90. XYLORHIZA Nutt., Trans. Amer. Philos. Soc. 2, 7:297. 1841.

 

Machaeranthera sect. Xylorhiza (Nutt.) Cronquist & Keck, Brittonia 9:239. 1957.

Machaeranthera ser. Integrifoliae Cronq. & Keck, Brittonia 9:239. 1957.

Machaeranthera ser. Fruticosae Cronq. & Keck, Brittonia 9:239. 1957.

 

Small shrubs, subshrubs, or perennial herbs, often white-barked, 1–15 dm tall, from a woody taproot and woody, branching, persistent stem base, glabrous to villous or tomentose, stipitate-glandular in some. Leaves linear to lanceolate or oblanceolate, oblong, or narrowly elliptic, 1–10 cm long, mostly 1-nerved, alternate, sessile, the margins entire to dentate-spinulose. Heads solitary, terminal on naked peduncles; involucres campanulate to hemispheric, 7–20 mm high; phyllaries in 3–6 graduate series, narrowly lanceolate, keeled, white-indurate toward the base with a green tip; receptacles folveolate to alveolate. Ray florets pistillate, fertile, (4–)12–60, the lamina white to light blue or purple, coiling at maturity. Disc florets perfect, fertile, gradually ampliate or narrowed below into a slender tube; style branches with lanceolate collecting appendages. Cypselae fusiform to linear or ovate, somewhat compressed, 3–8 mm long, 4-nerved, sericeous with long, silky, subappressed hairs; pappus in 2–3 series of numerous stout, often flattened, barbellate bristles of unequal length. Base chromosome number, x=6. (Greek, xylon, wood, rhiza, root; “the root only being woody.” – Nuttall 1841)

      Type species: Xylorhiza glabriuscula Nutt.

      A genus of eight species in the western USA and adjacent Mexico; all occur in the USA. All were considered by Cronquist and Keck (1957) to be primitive members of the genus Machaeranthera, where they were recently maintained (Cronquist 1994). Watson (1977), however, and other contemporary botanists, have recognized Xylorhiza as distinct genus characterized by the following set of features: strongly perennial subshrubs from a large, woody taproot with a woody, branching, persistent caudex, large, solitary heads with long phyllaries with erect or spreading apices, white or bluish rays, large cypselae, and vernal flowering. The base chromosome number of all species of Xylorhiza is x=6, in contrast to x=4 or 5 for Machaeranthera. Two sections were recognized by Watson: sect. Xylorhiza (subshrubs or perennial herbs) and sect. Californica T.J. Watson (shrubs).

      Watson (1977) noted, following early comments by Torrey and Gray, that some Xylorhiza are similar to South American species of Haplopappus DC. s. str. Recent molecular data (Morgan 1997; Morgan & Simpson 1992), however, are equivocal regarding the phylogeny of Xylorhiza, placing it either in a relatively primitive position within the subtribe (cpDNA restriction site) or as basal to the Blepharodon and Sideranthus groups of Machaeranthera (nuclear rDNA ITS sequence).

 

references

 

Cronquist, A. 1994. Intermountain flora. Vol. 5, Asterales. New York Botanical Garden, Bronx.

Cronquist, A. and D.D. Keck. 1957. A reconstitution of the genus Machaeranthera. Brittonia 9:231–239.

Morgan, D.R. 1997. Reticulate evolution in Machaeranthera (Asteraceae). Syst. Bot. 22:599–615.

Morgan, D.R. and B.B. Simpson. 1992. A systematic study of Machaeranthera (Asteraceae) and related groups using restriction site analysis of chloroplast DNA. Syst. Bot. 17:511–531.

Nuttall, T. 1841. Descriptions of new species and genera of plants in the natural order of the Compositae, collected ... during the years 1834 and 1835. Trans. Amer. Philos. Soc. 2, 7:283–453.

Watson, T.J., Jr. 1977. The taxonomy of Xylorhiza (Asteraceae – Astereae). Brittonia 29:199–216.

Watson, T.J., Jr. 1978. Chromosome numbers in Xylorhiza Nuttall (Asteraceae – Astereae). Madrono 25:205–210.

 

91. XYLOTHAMIA Nesom, Suh, Morgan, & Simpson, Sida 14:106. 1990.

 

Woody, evergreen subshrubs 0.2–3 m tall, from woody roots, not rhizomatous, stems and leaves minutely papillate in all but one species. Leaves linear-oblong to linear-lanceolate or obovate, 2–25 mm long, 1-nerved, entire, flat to involute-terete, strongly to weakly or not at all punctate-resinous. Heads more or less solitary and loosely aggregated to densely aggregated in a compact, corymbiform inflorescence; involucres campanulate to turbinate-campanulate, 3–8 mm high; phyllaries strongly graduated, narrowly oblong-lanceolate with white-indurated, enervate bases, with an apical, strongly viscid-glandular herbaceous patch, the margins hyaline; receptacles deeply alveolate, nearly smooth in X. triantha. Ray florets 0–8(–13), pistillate, fertile, the corollas yellow to white, barely exceeding the involucre. Disc florets perfect, fertile, the corollas yellow, 3–5 mm long, strongly zygomorphic, two of the sinuses cut nearly to the base of the throat, one very shallow (1/4–1/3 as deep as the former), and the other two intermediate in depth, the two short lobes erect, the others reflexed-coiling; style branches with ovate-lanceolate to linear-triangular collecting appendages. Cypselae subcylindric to turbinate, 1.5–2 mm long, without discernible nervation, moderately to densely sericeous; pappus of 1 series of persistent barbellate bristles. Base chromosome number, x=9. (Greek, xylon, wood, and -thamia in reference to its hypothesized close relationship with Euthamia.)

      Type species: Xylothamia triantha (Blake) Nesom.

      A genus of nine species mostly confined to the Chihuahuan Desert region and northeastern Mexico. All species of Xylothamia occur in Mexico; two also occur in southern Texas. These species were previously included in Ericameria (Urbatsch 1978), but morphological and molecular evidence indicates they may be more closely related to Euthamia (Nesom et al. 1990). Xylothamia is recognized by its subshrubby habit, loosely to compactly aggregated heads, phyllaries white-indurate on the lower half with the midrib not perceptibly extending through it to the base, the upper half with a prominent, glandular or herbaceous-glandular patch. The disc corollas are strongly zygomorphic, the lobes with two of the sinuses cut almost to the base of the throat, the others much shorter.

 

references

 

Nesom, G.L. 1992. A new species of Xylothamia (Asteraceae: Astereae) from the Cuatrocienegas area of Coahuila, Mexico. Phytologia 73:318–320.

Nesom, G.L., Y. Suh, D.A. Morgan, and B.B. Simpson. 1990. Xylothamia (Asteraceae: Astereae), a new genus related to Euthamia. Sida 14:101–116.

Urbatsch, L.E. 1978. The Chihuahuan Desert species of Ericameria (Asteraceae: Astereae). Sida 7:298–303.