Symphyotrichum pygmaeum |
Symphyotrichum oolentangiense |
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pygmy aster |
azure aster, skyblue aster |
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Habit | Perennials 1.5–15 cm, cespitose; with short, branched caudices, long-rhizomatous (both wiry). | Perennials 20–150 cm, cespitose; short-rhizomatous or with branched, woody caudices. |
Stems | 1–10+, decumbent to ascending (purple), sparsely or densely villous to woolly distally. |
1–5+, erect (straight), glabrate to hispidulous, distally pilosulous to strigillose in 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. |
thick, firm, margins entire or crenate-serrate, scabrous, apices mucronate, faces scabrous, abaxial strigose to piloso-strigose or hirsute, adaxial strongly strigose; basal withering by flowering, long-petiolate (petioles slightly winged, bases dilated, sheathing, ciliate), blades ovate to lance-ovate, 40–150(–180) × 10–40(–60) mm, bases ± cordate or rounded to attenuate, margins crenate-serrate to subentire, apices rounded or obtuse to acute; proximal cauline petiolate (petioles narrowly winged, clasping), blades ovate or ovate-lanceolate to lanceolate, 30–130 × 12–70 mm, gradually or ± abruptly reduced distally, bases rounded to attenuate, margins entire, scabrous, apices acute or attenuate, callus-pointed; distal sessile or sometimes short-petiolate and ± winged (appressed or ascending), blades lanceolate or linear-lanceolate to subulate, 5–80 × 1–10 mm, strongly reduced distally (more sharply so on branches), bases attenuate to cuneate or ± rounded, margins entire. |
Peduncles | densely villous to lanate distally, bracts 0. |
ascending, 0.2–6 cm, glabrate, densely bracteate, bracts linear-subulate, scabrous- or ciliate-margined, often revolute, grading with phyllaries. |
Involucres | hemispherico-campanulate, 9–12.5 mm. |
campanulate to cylindro-campanulate, 4.5–8 mm. |
Ray florets | 16–28; corollas purple to violet, laminae 12–18 × 2–3.2 mm. |
(10–)13–20(–25); corollas usually pale to azure blue to violet-purple, (rarely rosy, white or bluish white), laminae (5–)8–12(–14) × 1.4–1.7 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). |
(15–)20–25(–30); corollas light yellow turning deep purple, 4–5 mm, tubes much shorter than narrowly funnelform throats, lobes triangular to lanceolate, 0.4–0.7 mm (lobes sparsely hairy). |
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–)4–6 series, appressed or outer slightly spreading, lanceolate to oblong-lanceolate, strongly unequal, bases indurate 1/2–3/4, margins scarious, erose, hyaline, ciliolate, apical green zones diamond-shaped, apices acute to acuminate or caudate (then tips often involute), mucronulate to apiculate, faces glabrous. |
Heads | borne singly. |
in open, paniculiform arrays, branches ascending, stiff, sometimes long-arching and peduncles secund, ± ridged, densely leafy with small, ± appressed branch leaves, ± strigose. |
Cypselae | fusiform to cylindro-obconic, ± compressed, [size unknown], 4–7-nerved (faint), faces ± densely strigillose; pappi whitish to yellowish, 5–7.2 mm. |
dull purple or stamineous with purple streaks, oblong-obovoid, ± compressed, 1.8–2 mm, 4–5-nerved, faces glabrate to sparsely strigose; pappi cream or slightly rose-tinged, 3–4 mm. |
2n | = 32. |
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Symphyotrichum pygmaeum |
Symphyotrichum oolentangiense |
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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 | Open, dry, sandy, loamy, or rocky soils, dry to wet (seasonally drying) prairies, alvars, glades, bluffs, dunes, barrens, open deciduous woods, oak and/or pine savannas |
Elevation | 0–200+ m (0–700+ ft) | 50–500 m (200–1600 ft) |
Distribution |
AK; NT; NU |
AL; AR; FL; GA; IA; IL; IN; KS; LA; MI; MN; MO; MS; NE; NY; OH; OK; PA; SD; TN; TX; WI; ON; Ky ; Mexico (Coahuila)
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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.) |
A. G. Jones (1989) suggested that Symphyotrichum oolentangiense hybridizes with S. drummondii and S. laeve. Two color morphs, Aster azureus Lindley forma incarnatus Farwell and “forma albidus (the latter not validly published and incorrectly attributed to Steyermark by M. L. Fernald 1950), have been described but are not recognized here. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 20, p. 485. | FNA vol. 20, p. 507. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Aster pygmaeus, Aster sibiricus subsp. pygmaeus, Aster sibiricus var. pygmaeus, Eurybia pygmaea | Aster oolentangiensis, Aster azureus, Aster azureus var. poaceus, Aster azureus var. scabrior, Aster capillaceus, Aster poaceus, Aster vernalis |
Name authority | (Lindley) Brouillet & S. Selliah: Sida 21: 1635. (2005) | (Riddell) G. L. Nesom: Phytologia 77: 288. (1995) |
Web links |