Eurybia |
Eurybia conspicua |
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aster |
showy aster, showy wood-aster, western showy aster |
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Habit | Perennials, 10–120 cm (rhizomes long and slender to short and thick, sometimes cormoid, often becoming woody). | Plants 30–100 cm; forming loose clones, short-stipitate-glandular; rhizomes long to short, woody. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Stems | ascending to erect, usually simple, rarely branched proximally, glabrous or ± densely hairy, usually eglandular, sometimes stipitate-glandular. |
1, erect, seldom branched proximally, stout, proximally glabrate to villous and sparsely glandular (sometimes to base), distally glabrate, strongly glandular. |
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Leaves | basal and cauline; alternate; sessile or petiolate; blades cordate, ovate, obovate, elliptic, or oblong to spatulate, oblanceolate, or lanceolate, usually gradually reduced distally, margins entire or serrate, sometimes spinulose-serrate, faces glabrate to hairy, usually eglandular, sometimes stipitate-glandular. |
cauline, thick, ample, bases clasping, margins ± revolute, sharply serrate (rarely subentire) with ± mucronate teeth, veins prominent, apices acute to acuminate, mucronate, faces scabrous, adaxial veins villous; proximal cauline deciduous by flowering, winged-subpetiolate to sessile, blades oblanceolate to ovate or obovate, smaller than mid, bases tapering; mid usually sessile, sometimes subsessile, obovate or elliptic, (40–)58–140(–180) × (8–)20–50(–80) mm, bases cuneate to mostly rounded-subauriculate; distal (in arrays) sessile, ovate to oblanceolate, lanceolate, or elliptic, (8–)10–60(–90) × 2–28(–40) mm, strongly reduced distally. |
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Peduncles | sometimes sparsely hairy, stipitate-glandular; bracts usually 0, sometimes 1–3. |
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Involucres | cylindro-campanulate to broadly campanulate, (4–14(–16) ×) 4–25+ mm. |
campanulate, 9–12 mm, shorter than pappi. |
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Receptacles | flat to slightly convex, pitted, epaleate. |
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Ray florets | 5–60, pistillate, fertile; corollas white to purple (coiling at maturity). |
12–35; corollas blue or violet, (8–)10–15 × 1.2–2 mm. |
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Disc florets | 8–260, bisexual, fertile; corollas yellow, becoming purple at maturity, barely to abruptly ampliate, tubes shorter to longer than funnelform to campanulate throats, lobes 5, usually erect to spreading, sometimes ± reflexed, deltate, triangular, or lanceolate; style-branch appendages lanceolate. |
48–55; corollas yellow, 9–10 mm, slightly ampliate, tubes narrowly cylindric, slightly longer than narrowly funnelform throats, lobes erect, lanceolate, 0.7–1.3 mm. |
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Phyllaries | 20–140 in 3–7 series, 1-nerved (usually rounded adaxially, sometimes low-keeled), broadly ovate or oblong to oblanceolate, lanceolate, or linear, unequal, bases indurate (rarely wholly foliaceous), margins narrowly scarious (seldom herbaceous), often ciliolate (green zones ± basally truncate), in distal 1/3–3/4 of phyllary (outer) to less than 1/6 and only along midnerves (inner), apices obtuse to acute, faces glabrous, ± strigillose, puberulent, scabrellous, strigoso-villous, or villous, sometimes ± stipitate-glandular. |
34–55 in 4–5 series, midnerves translucent, strongly unequal, membranous, bases indurate, dark green distally, margins densely ciliate, apices spreading or ± squarrose, purple (mucro), acute or acuminate (sometimes mucronate), faces glabrous, densely stipitate-glandular; outer ovate or lanceolate; inner oblong-lanceolate, margins hyaline, often purplish distally, scarious. |
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Heads | radiate, usually in corymbiform arrays, rarely borne singly. |
5–50 in open corymbiform arrays. |
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Cypselae | cylindro-obconic to fusiform, ± compressed, 7–12(–18)-nerved, faces glabrous or sparsely to densely strigillose, eglandular; pappi persistent, of 35–70+, reddish, orange, cinnamon, tawny, tan, yellowish, or pinkish, unequal, soft to stiff, barbellate or barbellulate, often apically ± clavate bristles in 2–4 series. |
tan, fusiform, ± compressed, 3–4 mm, ribs 8–10, appressed-setose; pappi of cinnamon to pinkish bristles 9–10 mm, about as long as disc corollas. |
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x | = 9. |
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2n | = ca. 108, ca. 122. |
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Eurybia |
Eurybia conspicua |
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Phenology | Flowering summer–fall. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Habitat | Open, mesic conifer (spruce-fir, pine, or aspen-conifer) or aspen woods, from foothills to upper montane zone, mesic to dry meadows, forest openings, in somewhat clayey soils, adapted to spring fires | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Elevation | 300–2500 m (1000–8200 ft) | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Distribution |
North America; n Eurasia |
ID; MT; OR; SD; WA; WY; AB; BC; MB; SK
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Discussion | Species 23 (23, including 1 hybrid, in the flora). Eurybia traditionally has been treated within Aster in a broad sense. G. L. Nesom (1994b), in his review of North American asters, showed that Aster in a broad sense does not form a natural group and proposed splitting it into several genera, among which Eurybia is one. In his treatment, Nesom included Herrickia within Eurybia, as sect. Herrickia in subg. Eurybia. Such views were generally supported in molecular phylogenetic studies (J. C. Semple et al. 2002). L. Brouillet et al. (2004) showed, however, that Oreostemma, Herrickia, Eurybia, and Triniteurybia form a grade at the base of the Machaerantherinae and that Herrickia and Eurybia are distinct. The subgenera and sections proposed by G. L. Nesom (1994b), based on anterior taxonomy, could not be confirmed in the molecular studies cited above. I chose not to use subgeneric limits as proposed by Nesom because they may not reflect actual relationships. For instance, there is a clear gradation between members of sect. Calliastrum (Torrey & A. Gray) G. L. Nesom (subg. Eurybia) and sect. Heleastrum (de Candolle) G. L. Nesom. Also, I do not recognize sect. Eryngiifoliae (Alexander) G. L. Nesom distinct from sect. Heleastrum, as there is no clear demarcation between the two as currently defined. Finally, sect. Radulini (Rydberg) G. L. Nesom appears artificial to me, but currently there is no good way to reassign its species. The Eurybia radulina complex of western North America clearly constitute a group, but it is unclear whether the western E. conspicua or the eastern E. radula and E. saxicastelli are close to them. Members of other sections may have played a role in the reticulate evolution of sect. Eurybia, even though it is well marked by its cordate leaves and disc florets with long tubes and short, campanulate corollas. Therefore, species are described below in a rough taxonomic order, with diploids listed before polyploids of the same group. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Eurybia conspicua is a western boreo-montane taxon; it ranges from the Interior Mountains and Plateaus to the Rocky Mountains, and spreads onto the northern Great Plains in the aspen parklands-southern boreal forests of Canada, barely into western Manitoba. It is disjunct to the Black Hills (South Dakota) and Cypress Hills (Alberta-Saskatchewan). It stops at the Canadian Shield due to soil preferences (A. J. Breitung 1988). This taxon has the highest chromosome number in the genus. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 20, p. 365. | FNA vol. 20, p. 368. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Parent taxa | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Sibling taxa | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Subordinate taxa | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Synonyms | Aster subg. E. | Aster conspicuus | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Name authority | (Cassini) Cassini: in F. Cuvier, Dict. Sci. Nat. ed. 2, 16: 46. (1820) | (Lindley) G. L. Nesom: Phytologia 77: 259. (1995) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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