Cirsium pumilum |
Cirsium grahamii |
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pasture thistle |
Graham's thistle |
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Habit | Biennials or monocarpic perennials, 25–100 cm; sometimes perennating by root sprouts. | Biennials, 50–100 cm; taproots slender and fascicles of thick fibrous roots. | ||||
Stems | erect, villous with septate trichomes and sometimes thinly arachnoid tomentose; branches 0–few, distal, ascending. |
1, erect, thinly arachnoid and/or puberulent to short-pilose, sometimes ± glabrate; branches 0–4, 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. |
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. |
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Peduncles | 0–15+ cm (above distal leaves), leafy-bracted. |
10–30 cm. |
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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. |
hemispheric, 2–3 × 2–4 cm, thinly arachnoid or glabrous. |
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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. |
deep purple, 22–30 mm, tubes 13–18 mm, throats 4–5 mm, lobes 5–8 mm; style tips 4–4.5 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. |
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. |
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Heads | 1–few, borne singly at tips of main stem and branches, often closely subtended by 1–several bracts. |
1–5. |
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Cypselae | stramineous to brown, 3.5–5 mm, apical collars yellow or colored like body; pappi 35–45 mm. |
tan with dark speckles to dark purplish brown, 4–5.5 mm, apical collars not differently colored; pappi 13–18 mm. |
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2n | = 30. |
= 32 (Mexico). |
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Cirsium pumilum |
Cirsium grahamii |
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Phenology | Flowering Jul–Sep. | |||||
Habitat | Oak woodlands, coniferous forests, meadows, often in damp soil | |||||
Elevation | 1400–2600 m (4600–8500 ft) | |||||
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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AZ; NM; Mexico (Chihuahua, Durango, Sonora)
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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.) |
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.) |
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Key |
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Source | FNA vol. 19, p. 116. | FNA vol. 19, p. 124. | ||||
Parent taxa | Asteraceae > tribe Cardueae > Cirsium | Asteraceae > tribe Cardueae > Cirsium | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | Carduus pumilus | |||||
Name authority | (Nuttall) Sprengel: Syst. Veg. 3: 375. (1826) | A. Gray: Smithsonian Contr. Knowl. 5(6): 102. (1853) | ||||
Web links |