Cirsium pumilum |
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pasture thistle |
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Habit | Biennials or monocarpic perennials, 25–100 cm; sometimes perennating by root sprouts. | ||||
Stems | erect, villous with septate trichomes and sometimes thinly arachnoid tomentose; branches 0–few, distal, ascending. |
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Leaves | blades oblong-elliptic, 5–30+ × 2–10 cm, ± undulate, shallowly to deeply pinnatifid, lobes ovate to broadly triangular, usually separated by broad sinuses, spinose-dentate or lobed, main spines 1.5–7 mm, slender to stout, abaxial faces villous with septate trichomes, at least along veins, sometimes thinly arachnoid, adaxial faces villous with septate trichomes and thinly arachnoid tomentose or subglabrous; basal often present at flowering, bases tapered; principal cauline sessile, moderately reduced distally, bases often auriculate-clasping; distal reduced, similar to proximal. |
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Peduncles | 0–15+ cm (above distal leaves), leafy-bracted. |
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Involucres | broadly cylindric to ovoid, 3.5–5 cm, 2.5–3 cm diam. (appearing much wider and hemispheric to campanulate in pressed specimens), loosely arachnoid on phyllary margins or glabrate. |
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Corollas | pink to purple (white), 40–60 mm, tubes 20–35 mm, throats 11–15 mm, lobes 7–10 mm; style tips 3–7 mm. |
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Phyllaries | in 8–10 series, imbricate, ovate or lanceolate (outer) to lance-linear (inner), abaxial faces with ± prominent glutinous ridge, outer and middle appressed, apices ascending to spreading, spines 1.5–6 mm; apices of middle and inner narrowed and scabrid-denticulate, innermost spineless, tapered and entire or with expanded, erose-denticulate, flexuous tips. |
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Heads | 1–few, borne singly at tips of main stem and branches, often closely subtended by 1–several bracts. |
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Cypselae | stramineous to brown, 3.5–5 mm, apical collars yellow or colored like body; pappi 35–45 mm. |
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2n | = 30. |
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Cirsium pumilum |
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Distribution |
CT; DE; IA; IL; IN; MA; MD; ME; MI; MN; NC; NH; NJ; NY; OH; PA; RI; SC; VA; VT; WI; WV; ON; United States
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Discussion | Varieties 2 (2 in the flora). Flowers of Cirsium pumilum are reportedly sweetly scented. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 19, p. 116. | ||||
Parent taxa | Asteraceae > tribe Cardueae > Cirsium | ||||
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Synonyms | Carduus pumilus | ||||
Name authority | (Nuttall) Sprengel: Syst. Veg. 3: 375. (1826) | ||||
Web links |