Symphyotrichum spathulatum |
Symphyotrichum pygmaeum |
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western aster, western mountain aster |
pygmy aster |
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Habit | Perennials, 20–80 cm, colonial; long-rhizomatous. | Perennials 1.5–15 cm, cespitose; with short, branched caudices, long-rhizomatous (both wiry). | ||||||||
Stems | 1–5+, ascending to erect, glabrous or sparsely puberulent. |
1–10+, decumbent to ascending (purple), sparsely or densely villous to woolly distally. |
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Leaves | thin, margins entire, apices acute, faces glabrous or sparsely puberulent; basal persistent, petiolate, blades narrowly elliptic to obovate, 50–150 × 3–15 mm, attenuate, margins entire; proximal cauline sessile or subpetiolate, blades linear to narrowly elliptic, 50–150 × 2–15 mm, bases attenuate or cuneate; distal sessile, blades 30–60 × 2–10 mm, reduced distally, bases cuneate to rounded. |
firm, margins usually entire, sometimes remotely pauci-serrulate, sparsely villoso-ciliate, apices obtuse to acute, sometimes mucronate; basal often withering by flowering, petiolate (petioles widely winged, sheathing), blades spatulate, 5–19 × 2–4 mm, bases attenuate, apices rounded, faces glabrous or sparsely villous proximally; proximal sessile, blades lanceolate to oblong-lanceolate or (sometimes) -spatulate, 30–50 × 3–10 mm, bases ± clasping, apices obtuse to acute, faces glabrous or sparsely villous; distal sessile, blades lanceolate to oblong, 13–19 × 2–4.5 mm, bases clasping to cuneate, apices acute to obtuse, faces sparsely woolly, sometimes sparsely stipitate-glandular. |
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Peduncles | sparsely hairy, bracts 0–3+. |
densely villous to lanate distally, bracts 0. |
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Involucres | campanulate, 5–10 mm. |
hemispherico-campanulate, 9–12.5 mm. |
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Ray florets | 15–40; corollas violet, laminae 9–15 × 1–2 mm. |
16–28; corollas purple to violet, laminae 12–18 × 2–3.2 mm. |
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Disc florets | 30-80(–100); corollas yellow, sometimes becoming reddish, 4.5–6 mm, lobes triangular, 0.5–1 mm. |
53–55; corollas yellow, 5.6–6.5 mm, throats funnelform, lobes triangular, 0.5–0.8 mm (red or white clavate-hairy). |
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Phyllaries | in 3–5 series, narrowly oblong or linear (outer) to linear (inner), unequal, bases indurate, margins entire, green zones elliptic to lanceolate, apices usually acute, sometimes obtuse, faces glabrous or ± puberulent. |
in 3–4 series (dark purple), lance-oblong or oblong (outer) to linear-lanceolate or sometimes linear (inner), subequal, outer ± herbaceous, bases not indurate, margins herbaceous (outer) to narrowly scarious and erose proximally (inner), strongly purple, villoso-ciliate in green portion, green zones (inner) 1/2–2/3 of distal portions, apices acute to acuminate, inner sometimes apiculate, appressed to loose and squarrose (particularly outer), faces woolly to densely villous, sparsely to moderately stipitate-glandular. |
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Heads | in corymbiform to paniculiform arrays, branches usually few. |
borne singly. |
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Cypselae | brown, cylindric to obovoid, not compressed, 2.5–3.5 mm, ± 4-nerved, faces hairy; pappi whitish, 5–7 mm. |
fusiform to cylindro-obconic, ± compressed, [size unknown], 4–7-nerved (faint), faces ± densely strigillose; pappi whitish to yellowish, 5–7.2 mm. |
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Symphyotrichum spathulatum |
Symphyotrichum pygmaeum |
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Phenology | Flowering summer. | |||||||||
Habitat | Open, active, moist sand dunes, sandy or silty stream banks and terraces, usually cyclically disturbed gravelly tundra and tundra slopes | |||||||||
Elevation | 0–200+ m (0–700+ ft) | |||||||||
Distribution |
CA; CO; ID; MT; NM; NV; OR; UT; WA; WY; AB; BC; NT; nw Mexico
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AK; NT; NU |
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Discussion | Varieties 3 (3 in the flora). Symphyotrichum spathulatum is a variable species, widespread in montane regions of western North America. It hybridizes with S. bracteolatum, S. foliaceum, and S. hendersonii. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Of conservation concern. Symphyotrichum pygmaeum has long been included within or associated with Eurybia sibirica. Though similar in appearance, the two species can be distinguished by the glands present on S. pygmaeum on the distal leaves and phyllaries. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 20, p. 534. | FNA vol. 20, p. 485. | ||||||||
Parent taxa | Asteraceae > tribe Astereae > Symphyotrichum > subg. Symphyotrichum > sect. Occidentales | Asteraceae > tribe Astereae > Symphyotrichum > subg. Virgulus | ||||||||
Sibling taxa | ||||||||||
Subordinate taxa | ||||||||||
Synonyms | Aster spathulatus | Aster pygmaeus, Aster sibiricus subsp. pygmaeus, Aster sibiricus var. pygmaeus, Eurybia pygmaea | ||||||||
Name authority | (Lindley) G. L. Nesom: Phytologia 77: 291. (1995) | (Lindley) Brouillet & S. Selliah: Sida 21: 1635. (2005) | ||||||||
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