Cirsium flodmanii |
Cirsium douglasii |
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chardon de Flodman, Flodman's thistle, prairie thistle |
Brewer's thistle, California swamp or Douglas' thistle, Douglas' thistle, swamp thistle |
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Habit | Perennials 30–140 cm; horizontal runner roots that produce root sprouts. | Biennials or short-lived monocarpic perennials, 60–250 cm; taprooted. | ||||
Stems | 1–several, erect, gray- or white-tomentose; branches 0–few, ascending. |
1–several, erect or ascending, densely gray-tomentose; branches few–many, ascending to spreading. |
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Leaves | blades oblong-oblanceolate to narrowly elliptic, 4–40 × 1–10 cm, bases usually not decurrent, finely spiny-toothed and undivided to coarsely toothed or deeply pinnatifid, lobes broadly triangular to linear-lanceolate, often revolute-margined, main spines 1–7 mm, abaxial faces white-tomentose, adaxial faces green, thinly tomentose, ± glabrate; basal usually absent or withered at flowering, winged petiolate; principal cauline proximally winged-petiolate, distally sessile, well distributed, gradually reduced, bases usually not decurrent; distal cauline well developed. |
blades oblong-elliptic to obovate, 10–60 × 2–15 cm, unlobed or shallowly to deeply pinnatifid, lobes lanceolate to ovate-triangular, ascending to spreading, entire to coarsely dentate or lobed, main spines slender to stout, 2–30 mm, faces densely gray-tomentose, rarely glabrate; basal present at flowering, petiolate; principal cauline well distributed, proximal winged-petiolate, distal sessile, bases auriculate-clasping or decurrent as a spiny wing 1–3 cm; distalmost well separated, bractlike. |
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Peduncles | 0–5 cm (elevated above distal leaves). |
0–4(–8) cm. |
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Involucres | ovoid to broadly campanulate, 2–3.5 × 2.5–3.5 cm, thinly arachnoid. |
ovoid to hemispheric, 1.5–3 cm, 2–4.5 cm diam, loosely arachnoid on phyllary margins or glabrate. |
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Corollas | purple (white), 23–36 mm, tubes 12–15 mm, throats 6–8.5 mm, lobes 5–9 mm; style tips 4–7 mm. |
rose-purple (white or pinkish-tinged), 18–21 mm, tubes 8–9 mm, throats 5–6 mm (abruptly expanded), lobes 5–6 mm; style tips 3–4.5 mm. |
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Phyllaries | in 7–12 series, strongly imbricate, greenish with subapical darker central zone, ovate or lanceolate (outer) to linear (inner), abaxial faces with prominent glutinous ridge; outer and middle entire, bodies appressed, entire, acute, spines abruptly spreading, slender, 2–4 mm; apices of inner spreading, flexuous, narrow, flattened, finely serrulate, ± scabrous. |
in 6–8 series, imbricate, often with dark purple patch near tip, ovate-lanceolate (outer) to linear-lanceolate (inner), abaxial faces with linear to elliptic glutinous ridge; outer and middle appressed, entire, spines spreading, 1–9 mm; apices of inner often purple-tinged, often flexuous, flattened, spineless, scabrid. |
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Heads | erect, borne singly and terminal on main stem and branches, or few in corymbiform arrays from distal axils (not subtended by ring of spiny-margined bracts). |
10–many, often crowded at branch tips, collectively forming paniculiform arrays. |
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Cypselae | light brown, 3–5 mm, apical collars stramineous, 0.5–1 mm; pappi (white or tawny) 20–30 mm. |
dark brown to black, 5–6 mm, apical collars not differentiated; pappi 15–20 mm. |
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2n | = 22, 24. |
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Cirsium flodmanii |
Cirsium douglasii |
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Phenology | Flowering summer (Jun–Sep). | |||||
Habitat | Tallgrass, mixedgrass, shortgrass prairies, meadows, pastures, often in damp soil | |||||
Elevation | 100–2400 m (300–7900 ft) | |||||
Distribution |
CO; IA; IL; KS; MI; MN; MT; ND; NE; SD; WI; WY; AB; MB; ON; QC; SK
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CA; NV; OR
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Discussion | Cirsium flodmanii ranges from Saskatchewan and Alberta south through the northern Great Plains and intermountain valleys of Montana and Wyoming to northeastern Colorado and east through the prairies to Minnesota and Iowa, and in widely scattered locations eastward to northern Illinois, southern Wisconsin, southern Ontario, and southern Quebec. It is known to hybridize with C. muticum and C. undulatum. Hybrids between C. flodmanii and C. undulatum are highly sterile with numerous meiotic irregularities (S. Dabydeen 1987). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Varieties 2 (2 in the flora). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 19, p. 120. | FNA vol. 19, p. 133. | ||||
Parent taxa | Asteraceae > tribe Cardueae > Cirsium | Asteraceae > tribe Cardueae > Cirsium | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | Carduus flodmanii, C. oblanceolatum | |||||
Name authority | (Rydberg) Arthur: Torreya 12: 34. (1912) | de Candolle: in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 6: 643. (1838) | ||||
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