Symphyotrichum pygmaeum |
Symphyotrichum welshii |
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pygmy aster |
Welsh's aster |
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Habit | Perennials 1.5–15 cm, cespitose; with short, branched caudices, long-rhizomatous (both wiry). | Perennials, 30–100 cm colonial; rhizomes shallow and long, often relatively thick (those of the season each producing a distal rosette near the parent plant). |
Stems | 1–10+, decumbent to ascending (purple), sparsely or densely villous to woolly distally. |
1–2, ascending to erect (sometimes lax, sometimes reddish), glabrous or sparsely strigoso-villosulous distally (arrays). |
Leaves | 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. |
(adaxially green, abaxially pale green, sometimes glaucous) thin (proximal) to stiff (distal), margins serrulate (proximal) or entire or nearly so, ± revolute, scabrous, apices mucronulate or sometimes callous-pointed, faces glabrous; basal withering by flowering, petiolate (petioles narrowly winged, sheathing), blades oblanceolate to spatulate, 10–40+ × 4–9+ mm, bases attenuate, margins entire, apices obtuse; proximal cauline withering by flowering, sessile or winged-petiolate, blades lanceolate to oblanceolate, 50–150 × 8–11 mm, bases slightly clasping, margins sparsely serrulate, apices acute; distal sessile, blades linear to linear-lanceolate, 50–130 × 4–6 mm, gradually reduced distally, bases ± clasping, apices acute. |
Peduncles | densely villous to lanate distally, bracts 0. |
0.5–2 cm, scabro-villosulous, bracts linear, scabro-ciliolate. |
Involucres | hemispherico-campanulate, 9–12.5 mm. |
cylindro-campanulate, 4–7 mm. |
Ray florets | 16–28; corollas purple to violet, laminae 12–18 × 2–3.2 mm. |
18–25; corollas pink to white, laminae 9–12 × 0.8–1.5 mm. |
Disc florets | 53–55; corollas yellow, 5.6–6.5 mm, throats funnelform, lobes triangular, 0.5–0.8 mm (red or white clavate-hairy). |
23–60; corollas pale yellow, 3.8–6.4 mm, tubes shorter than funnelform throats, lobes narrowly triangular, 0.4–0.8 mm. |
Phyllaries | 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. |
in 3–4 series, lanceolate (outer) to linear (inner), ± unequal, bases indurate, margins hyaline, erose, distally scabro-ciliolate to ciliolate, green zones ± foliaceous (outer) or lanceolate, apices acute to acuminate, sometimes purplish, faces glabrous. |
Heads | borne singly. |
in open, slender, leafy, paniculiform or racemiform arrays, branches ascending. |
Cypselae | fusiform to cylindro-obconic, ± compressed, [size unknown], 4–7-nerved (faint), faces ± densely strigillose; pappi whitish to yellowish, 5–7.2 mm. |
pinkish tan (nerves stramineous), obovoid, ± compressed, 0.8–1.6 mm, 3–5-nerved, faces sparsely strigillose; pappi white, 2.8–5.3 mm. |
2n | = 16. |
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Symphyotrichum pygmaeum |
Symphyotrichum welshii |
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Phenology | Flowering summer. | Flowering Aug–Oct. |
Habitat | Open, active, moist sand dunes, sandy or silty stream banks and terraces, usually cyclically disturbed gravelly tundra and tundra slopes | Wet soils in dry areas, hanging gardens, seeps, wet ledges, stream banks |
Elevation | 0–200+ m (0–700+ ft) | 1300–2300 m (4300–7500 ft) |
Distribution |
AK; NT; NU |
AZ; ID; MT; UT; WY |
Discussion | 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.) |
Of conservation concern. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 20, p. 485. | FNA vol. 20, p. 523. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Aster pygmaeus, Aster sibiricus subsp. pygmaeus, Aster sibiricus var. pygmaeus, Eurybia pygmaea | Aster welshii |
Name authority | (Lindley) Brouillet & S. Selliah: Sida 21: 1635. (2005) | (Cronquist) G. L. Nesom: Phytologia 77: 294. (1995) |
Web links |