Symphyotrichum robynsianum |
Symphyotrichum concolor |
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aster à longues feuilles, longleaf aster, Robyns' aster |
eastern silver American-aster, eastern silver aster, eastern silvery aster |
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Habit | Perennials, 10–80 cm, colonial; long-rhizomatous. | Perennials, 30–80 cm, cespitose; with cormoid, woody caudices. | ||||
Stems | 1, erect (± flexuous, often reddish), glabrous, hairy in lines distally. |
1–10+, ascending to erect (light to dark brown), glabrous or densely canescent distally. |
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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. |
(green to graysih) soft to firm; basal withering by flowering, sessile, blades (1–3-nerved) elliptic-lanceolate, 10–43 × 5–15 mm, bases attenuate, margins usually entire, rarely remotely serrate, piloso-ciliate, apices acute to obtuse, faces silvery silky-pilose to sparsely pilose; proximal cauline withering by flowering, sessile, blades oblanceolate, 20–35 × 5–15 mm, bases rounded, subclasping, margins entire, scabrous to silky-pilose, apices acute to obtuse, cuspidate mucronate, faces ± densely silky; distal sessile, blades usually oblong to lanceolate, rarely ovate, 9–15 × 1.8–5 mm, reduced distally, bases cuneate, margins entire, apices acute, mucronate, faces ± densely silky or sparsely strigose, sometimes glabrate (var. devestitum). |
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Peduncles | glabrous or ± densely pilose in lines, bracts 1–4, linear, sometimes inrolled distally, clasping, ciliate, distal 1–2 often subtending and surpassing involucres. |
densely hairy, bracts becoming linear, grading into phyllaries. |
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Involucres | campanulate, 5–8.5 mm. |
campanulate to narrowly campanulate, 5–7 mm. |
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Ray florets | 20–35; corollas dark blue-violet, seldom white, laminae 8–13 × 1–1.5 mm. |
8–12; corollas rose-purple, rarely white, laminae 4–9 × 1–1.5 mm. |
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Disc florets | (18–)23–40; corollas yellow, 4–6.5 mm, tubes shorter than funnelform throats, lobes lanceolate, 0.8–1 mm. |
(9–)11–17(–21); corollas pink turning purple, 4.5–6 mm, tubes shorter than narrowly funnelform throats (thinly puberulent), lobes triangular, 0.4–0.7 mm. |
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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, lanceolate-oblong, strongly unequal, bases (tan) ± indurate, margins scarious proximally, green distally, green zones restricted to apex, obscured by hair, apices usually acute, sometimes acuminate, usually mucronate, sometimes subspinulose, faces ± densely silky. |
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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, paniculiform (virgate) arrays (1–3(–5) per branch). |
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Cypselae | tan, obovoid, compressed, ca. 2.2–2.4 mm, 5–6-nerved, faces sparsely strigillose; pappi pinkish, 7–8 mm. |
obovoid, not compressed, 2.5–3.5 mm, 7–10-nerved, faces densely strigose; pappi tan, (3.5–)4–6 mm. |
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2n | = 64, 80. |
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Symphyotrichum robynsianum |
Symphyotrichum concolor |
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Phenology | Flowering Aug–Sep. | |||||
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 | |||||
Elevation | 10–400 m (0–1300 ft) | |||||
Distribution |
MI; MN; WI; MB; ON; QC
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AL; DE; FL; GA; KY; LA; MA; MD; MS; NC; NJ; NY; RI; SC; TN; VA
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Discussion | The name Aster longifolius Lamarck has been misapplied to this taxon. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Varieties 2 (2 in the flora). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 20, p. 530. | FNA vol. 20, p. 492. | ||||
Parent taxa | Asteraceae > tribe Astereae > Symphyotrichum > subg. Symphyotrichum > sect. Symphyotrichum | Asteraceae > tribe Astereae > Symphyotrichum > subg. Virgulus | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | Aster robynsianus | Aster concolor, Lasallea concolor, Virgulus concolor | ||||
Name authority | (J. Rousseau) Brouillet & Labrecque: Phytologia 82: 138. (1997) | (Linnaeus) G. L. Nesom: Phytologia 77: 278. (1995) | ||||
Web links |