Symphyotrichum robynsianum |
Symphyotrichum parviceps |
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aster à longues feuilles, longleaf aster, Robyns' aster |
smallhead aster, smallhead or small white aster |
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Habit | Perennials, 10–80 cm, colonial; long-rhizomatous. | Perennials (sometimes short-lived), 30–100 cm, colonial or cespitose; long-rhizomatous or with short, branched caudices. |
Stems | 1, erect (± flexuous, often reddish), glabrous, hairy in lines distally. |
1–3+, ascending to erect (straight, slender, reddish), sparsely to densely pilosulous to hirtellous, proximally glabrescent. |
Leaves | stiff, margins sparsely serrulate or entire, ± revolute, scabrous, apices acute to acuminate, mucronulate, faces glabrous, sometimes midveins hairy; basal withering by flowering, long-petiolate, petioles narrowly winged, bases sheathing, blades lanceolate, ca. 20 × 3–5 mm, slightly attenuate to narrowly cuneate; proximal cauline withering by flowering, sessile or subpetiolate, blades linear-lanceolate to -oblanceolate, 100–200 × 4–8 mm, bases cuneate to attenuate, clasping; distal sessile, blades linear-lanceolate to linear, 10–110 × 1–7 mm, progressively reduced distally, bases cuneate to rounded, slightly clasping or not, margins entire. |
thin, margins strigoso-ciliate to scabrous, apices mucronulate, abaxial faces glabrate to sparsely pilose and midveins ± pilose to glabrate, adaxial glabrous or glabrate to pilosulous or hirsutulous; basal withering by flowering, subpetiolate, blades oblanceolate to narrowly oblanceolate or spatulate, 10–40 × 3–7 mm, bases cuneate, sheathing, margins sparsely serrate apically, apices obtuse, mucronate, faces sparsely pilose; proximal cauline usually withering by flowering, sessile or subsessile (often with axillary clusters of small leaves), blades oblanceolate to lanceolate, 40–80 × 2–5 mm, bases cuneate, margins entire or serrulate apically; distal sessile, blades linear to subulate, 4–100 × 1–6 mm, reduced distally, bases cuneate, margins entire to weakly serrulate, faces glabrate or glabrous. |
Peduncles | glabrous or ± densely pilose in lines, bracts 1–4, linear, sometimes inrolled distally, clasping, ciliate, distal 1–2 often subtending and surpassing involucres. |
3–20(–40) mm, glabrate or glabrous, bracts 3–6+, appressed or ascending, linear to subulate, 2–4 mm, scabrous, aristate, glabrous, grading into phyllaries. |
Involucres | campanulate, 5–8.5 mm. |
cylindric to cylindro-campanulate, (2.7–)3.1–4.1(–4.9) × ± 3 mm. |
Ray florets | 20–35; corollas dark blue-violet, seldom white, laminae 8–13 × 1–1.5 mm. |
(9–)11–17(–23); corollas usually white, seldom pink, laminae (3.7–)5–5.5(–7.3) × 0.6–1.3 mm. |
Disc florets | (18–)23–40; corollas yellow, 4–6.5 mm, tubes shorter than funnelform throats, lobes lanceolate, 0.8–1 mm. |
5–16(–28); corollas pale yellow becoming purplish, (2.3–)2.5–3.3(–3.7) mm, tubes shorter than narrowly funnelform throats, lobes lanceolate, 0.4–0.8 (ratio 0.25) mm. |
Phyllaries | in 3–4 series, oblong-lanceolate, subequal, bases indurate 1/3–3/4, margins scarious, erose, hyaline, ciliate proximally, sparsely ciliolate distally, green zones lanceolate to linear, sometimes outer ± foliaceous, apices acuminate to long-acuminate, often foliaceous, mucronate to apiculate, faces glabrous, eglandular. |
in 3–5 series, appressed, subulate (outermost) to oblong-lanceolate to linear-lanceolate (inner) or linear (innermost), unequal, bases indurate 1/2–3/4, margins scarious, erose, hyaline, sparsely ciliolate or not, green zones lanceolate, apices slightly spreading, often purplish, often involute, acute to acuminate or cuspidate, sometimes aristate, faces usually glabrous, sometimes glabrate. |
Heads | in elongate, open, narrow, paniculiform or racemiform arrays, branches ascending, short, leafy, branch leaves smaller and reduced distally (heads 1–3 per branch). |
in narrow or wide, pyramidal, paniculiform arrays, branches ascending or arching, secondary branches (10 cm or less) secund and erect, densely leafy, heads crowded, sparsely to moderately pilose. |
Cypselae | tan, obovoid, compressed, ca. 2.2–2.4 mm, 5–6-nerved, faces sparsely strigillose; pappi pinkish, 7–8 mm. |
whitish or gray, obovoid, compressed, 0.8–1.5 × 0.4–0.6 mm, 3–4-nerved, faces sparsely to moderately strigillose; pappi white, 3–4 mm. |
2n | = 64, 80. |
= 16, 32, 48. |
Symphyotrichum robynsianum |
Symphyotrichum parviceps |
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Phenology | Flowering Aug–Sep. | Flowering Aug–Oct. |
Habitat | Wet or damp, open, sandy, gravelly, or rocky grounds, often calcareous, cracks in rocky stream or lake shores, limestone alvars, seasonally wet glades and swales, jackpine outwash plains | Open, dry, sandy, or loamy soils, open woods, barrens, prairies, fields, roadsides, old cemeteries |
Elevation | 10–400 m (0–1300 ft) | 200–400 m (700–1300 ft) |
Distribution |
MI; MN; WI; MB; ON; QC
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AR; IA; IL; KS; MO; OK |
Discussion | The name Aster longifolius Lamarck has been misapplied to this taxon. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 20, p. 530. | FNA vol. 20, p. 511. |
Parent taxa | Asteraceae > tribe Astereae > Symphyotrichum > subg. Symphyotrichum > sect. Symphyotrichum | Asteraceae > tribe Astereae > Symphyotrichum > subg. Symphyotrichum > sect. Symphyotrichum |
Sibling taxa | ||
Synonyms | Aster robynsianus | Aster ericoides var. parviceps, Aster parviceps, Aster pilosus subsp. parviceps |
Name authority | (J. Rousseau) Brouillet & Labrecque: Phytologia 82: 138. (1997) | (E. S. Burgess) G. L. Nesom: Phytologia 77: 288. (1995) |
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