Cirsium virginianum |
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Virginia thistle |
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Habit | Biennials or perennials, 60–150(–200) cm; crown sprouts from cluster of fibrous roots, these often tuberous-thickened. |
Stems | usually single, erect, thinly appressed-tomentose, ± glabrate in age; branches 0–few in distal 1/3, ascending. |
Leaves | very numerous, firm-textured, blades 3–15 cm, thick, ± rigid, linear or linear-elliptic, 0.5–2 cm wide and spinulose, or narrowly ovate, 2–4 cm wide, deeply lobed, lobes remote, spreading, separated by broad sinuses, few toothed or lobed, margins often revolute, main spines slender, 3–5(–9) mm, abaxial faces white-tomentose, adaxial green, glabrous or thinly tomentose; basal usually absent at flowering, winged-petiolate; proximal cauline usually absent at flowering, well separated, winged-petiolate; middle and distal numerous (30–70+), sessile, well distributed, gradually reduced distally, bases tapered, not decurrent; distal linear, entire or few lobed, ca. 1 cm. |
Peduncles | 10–15 cm (not overtopped by distal leaves). |
Involucres | ovoid to cylindric or narrowly campanulate, 1.7–2.4 × 1–2 cm, glabrous or outer phyllaries very thinly tomentose. |
Corollas | purple, 21–26 mm, tubes 8.5–11 mm, throats 6–8 mm (noticeably wider than tubes), lobes 4–8 mm; style tips 3.5–5 mm. |
Phyllaries | in 8–13 series, strongly imbricate, light green to brownish with dark apices, ovate (outer) to narrowly linear-elliptic (inner), abaxial faces with evident, narrow glutinous ridge; outer and middle appressed, bodies entire, apices erect or spreading, muticous to short-spinose, spines ascending to spreading, weak, 1–2 mm; apices of inner all straight and entire or innermost ± flexuous, erose. |
Heads | 1–10+ in open, corymbiform or paniculiform arrays. |
Cypselae | dark brown, 4–5 mm, apical collars yellowish, 0.5–1; pappi 17–20 mm. |
2n | = 28. |
Cirsium virginianum |
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Phenology | Flowering summer–fall (Aug–Oct). |
Habitat | Moist savannas, pine barrens, coastal plain bogs |
Elevation | 0–150 m (0–500 ft) |
Distribution |
DE; FL; GA; NC; NJ; SC; VA
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Discussion | Cirsium virginianum occurs on the Atlantic coastal plain from Delaware to Florida. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 19, p. 118. |
Parent taxa | |
Sibling taxa | |
Synonyms | Carduus virginianus, Carduus revolutus, C. revolutum |
Name authority | (Linnaeus) Michaux: Fl. Bor.-Amer. 2: 90. (1803) |
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