Symphyotrichum tradescantii |
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aster de Tradescant, shore aster, Tradescant's American-aster, Tradescant's aster |
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Habit | Perennials, 5–70 cm, cespitose; short-rhizomatous. |
Stems | 1–5+, ascending to erect (straight, slender, 1–2.5(–3) mm diam.), glabrous. |
Leaves | thin, margins scabrous to scabrellous or eciliate, apices mucronulate, faces glabrous; basal persistent or withering by flowering, petiolate (petioles slightly winged, sheathing), blades spatulate to elliptic or oblanceolate, 10–40 × 5–11 mm, bases cuneate to attenuate, margins crenate-serrate, apices obtuse to acute; proximal cauline persistent or withering by flowering, ± broadly winged-petiolate or sessile, blades oblong, lanceolate or elliptic-lanceolate to oblanceolate, or linear-lanceolate, 20–100 × 3–9 mm, bases attenuate to cuneate, slightly clasping, margins serrulate or entire; distal sessile, blades oblanceolate to linear-lanceolate or linear, 10–60 × 1–7 mm, gradually reduced distally, bases cuneate to tapering, margins serrulate or entire, apices acute to acuminate. |
Peduncles | ascending, 0.2–2.5+ cm, glabrous, bracts 1–4, subulate to linear. |
Involucres | cylindro-campanulate, 3.3–4.5(–5) mm. |
Ray florets | 14–27; corollas white, laminae 4.3–8.2 × 0.7–0.8 mm. |
Disc florets | 20–30; corollas pale yellow becoming purplish, 3–4.1 mm, tubes shorter to nearly equaling funnelform throats, lobes lanceolate, 0.5–1 mm. |
Phyllaries | in 4–5 series oblong-lancoelate (outer) to linear-lanceolate (inner) or linear (innermost), unequal, bases indurate 1/2+, margins scarious, erose, hyaline, ciliolate, green zones lanceolate, apices acute to acuminate or caudate, mucronulate or apiculate, sometimes purplish, faces glabous. |
Heads | {(10–)25–100} in paniculiform arrays, branches ascending (1–10 heads per branch). |
Cypselae | tan (nerves stramineous), obovoid, ± compressed, 3.5–4 mm, 4–5-nerved, faces strigillose; pappi white, 3–3.6 mm. |
2n | = 16, 32. |
Symphyotrichum tradescantii |
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Phenology | Flowering Jul–Aug(–Sept). |
Habitat | Damp, rocky and gravelly shores, silt- or loam-filled cracks in rocky rapids of streams or along freshwater estuaries |
Elevation | 0–200+ m (0–700+ ft) |
Distribution |
MA; ME; NH; NJ; NY; RI; VT; NB; NF; NS; QC
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Source | FNA vol. 20, p. 516. |
Parent taxa | Asteraceae > tribe Astereae > Symphyotrichum > subg. Symphyotrichum > sect. Symphyotrichum |
Sibling taxa | |
Synonyms | Aster tradescantii |
Name authority | (Linnaeus) G. L. Nesom: Phytologia 77: 293. (1995) |
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