Cirsium virginianum |
Cirsium grahamii |
|
---|---|---|
Virginia thistle |
Graham's thistle |
|
Habit | Biennials or perennials, 60–150(–200) cm; crown sprouts from cluster of fibrous roots, these often tuberous-thickened. | Biennials, 50–100 cm; taproots slender and fascicles of thick fibrous roots. |
Stems | usually single, erect, thinly appressed-tomentose, ± glabrate in age; branches 0–few in distal 1/3, ascending. |
1, erect, thinly arachnoid and/or puberulent to short-pilose, sometimes ± glabrate; branches 0–4, 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. |
blades oblanceolate to oblong-elliptic, 20–30 × 3–8 cm, spinulose and otherwise entire or coarsely dentate to deeply pinnatifid, lobes entire or coarsely few toothed or lobed, main spines slender, 3–6 mm, abaxial ± persistently gray-tomentose, sometimes pilose along veins, adaxial faces thinly arachnoid and ± glabrate; basal often present at flowering, sessile or narrowly winged-petiolate; principal cauline gradually winged-petiolate or sessile, reduced distally, bases sometimes clasping or short-decurrent; distal cauline ascending, becoming bractlike, narrow, lobed or not. |
Peduncles | 10–15 cm (not overtopped by distal leaves). |
10–30 cm. |
Involucres | ovoid to cylindric or narrowly campanulate, 1.7–2.4 × 1–2 cm, glabrous or outer phyllaries very thinly tomentose. |
hemispheric, 2–3 × 2–4 cm, thinly arachnoid or glabrous. |
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. |
deep purple, 22–30 mm, tubes 13–18 mm, throats 4–5 mm, lobes 5–8 mm; style tips 4–4.5 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. |
in ca. 8 series, imbricate, proximally brownish, distally dark purplish, lanceolate to linear, margins of outer hispidulous-ciliolate, spiny fringed, pinnately spiny or with scarious appendages, abaxial faces with prominent, glutinous ridge; outer and middle appressed or only apices spreading, bodies minutely spinulose-denticulate, spines erect to ascending, 1.5–2.5 mm; apices of inner phyllaries often flexuous, flat, scabridulous. |
Heads | 1–10+ in open, corymbiform or paniculiform arrays. |
1–5. |
Cypselae | dark brown, 4–5 mm, apical collars yellowish, 0.5–1; pappi 17–20 mm. |
tan with dark speckles to dark purplish brown, 4–5.5 mm, apical collars not differently colored; pappi 13–18 mm. |
2n | = 28. |
= 32 (Mexico). |
Cirsium virginianum |
Cirsium grahamii |
|
Phenology | Flowering summer–fall (Aug–Oct). | Flowering Jul–Sep. |
Habitat | Moist savannas, pine barrens, coastal plain bogs | Oak woodlands, coniferous forests, meadows, often in damp soil |
Elevation | 0–150 m (0–500 ft) | 1400–2600 m (4600–8500 ft) |
Distribution |
DE; FL; GA; NC; NJ; SC; VA
|
AZ; NM; Mexico (Chihuahua, Durango, Sonora)
|
Discussion | Cirsium virginianum occurs on the Atlantic coastal plain from Delaware to Florida. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Cirsium grahamii occurs in the mountains of southeastern Arizona and southwestern New Mexico. It forms hybrid swarms with C. parryi and C. scariosum var. coloradense in the White Mountains of Arizona. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 19, p. 118. | FNA vol. 19, p. 124. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Carduus virginianus, Carduus revolutus, C. revolutum | |
Name authority | (Linnaeus) Michaux: Fl. Bor.-Amer. 2: 90. (1803) | A. Gray: Smithsonian Contr. Knowl. 5(6): 102. (1853) |
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