Cirsium flodmanii |
Cirsium cymosum |
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chardon de Flodman, Flodman's thistle, prairie thistle |
graygreen thistle, peregrine thistle |
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Habit | Perennials 30–140 cm; horizontal runner roots that produce root sprouts. | Biennials or perennials, 25–120 cm, pubescence a mixture of fine, non-septate arachnoid trichomes and coarser, septate trichomes, especially along stems and on midveins on abaxial leaf faces, usually ± loose and irregularly deciduous from leaves in age; taprooted. | ||||
Stems | 1–several, erect, gray- or white-tomentose; branches 0–few, ascending. |
usually 1, erect, ± gray-tomentose, sometimes villous with septate trichomes; branches 0–10+, usually arising in distal 1/2, ascending, usually reaching a ± common height. |
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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 linear-oblong to oblanceolate or elliptic, 10–30 × 3–7 cm, shallowly to deeply pinnatifid with 3–8 pairs of lobes, longer than 2 cm, lobes well separated, linear to triangular-ovate, dentate to lobed proximally, main spines slender, 2–7 mm, faces green to gray, thinly to densely arachnoid-tomentose with fine, non-septate trichomes, sometimes villous with septate trichomes along veins, usually ± loose and irregularly deciduous from leaves in age; basal often present at flowering, sessile or winged-petiolate; principal cauline mostly in proximal 1/2, winged-petiolate or sessile, bases narrowed, auriculate, veins often prominently raised on abaxial faces; distal sessile, auriculate-clasping or short-decurrent 1–10 mm, progressively reduced becoming bractlike, often unlobed or less deeply divided and sometimes spinier than proximal. |
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Peduncles | 0–5 cm (elevated above distal leaves). |
(0–)2–15 cm. |
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Involucres | ovoid to broadly campanulate, 2–3.5 × 2.5–3.5 cm, thinly arachnoid. |
ovoid to hemispheric or campanulate, 2–3 × 1.5–3.5 cm, ± arachnoid-floccose, often 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. |
creamy white to purplish, 20–31 mm, tubes 8–14 mm, throats 5.5–10 mm, lobes 6–7 mm; style tips 4–6 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 8–10 series, subequal to strongly imbricate, green, linear to lanceolate (outer) to linear (inner), entire, abaxial faces with inconspicuous to prominent glutinous ridge; outer and mid bodies loosely spreading to ascending or appressed, apices subappressed to ascending or spreading, flat, spines ascending to spreading, fine, 2–4 mm; apices of inner commonly flexuous or reflexed, narrow, flat, scarious. |
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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). |
borne singly, terminal on main stem and branches, sometimes also in distal axils, erect, not subtended by well-developed leaves, collectively forming corymbiform or racemiform 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. |
tan to dark brown, 5–7.5 mm, apical collars not differentiated; pappi 16–25 mm. |
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2n | = 22, 24. |
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Cirsium flodmanii |
Cirsium cymosum |
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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; ID; MT; NV; OR; WY
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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). Past floras have treated Cirsium cymosum and C. canovirens as separate species. In my examination of these plants across their combined ranges I realized that they are connected by numerous intermediates and that I could find no characters that consistently distinguish them. (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. 136. | ||||
Parent taxa | Asteraceae > tribe Cardueae > Cirsium | Asteraceae > tribe Cardueae > Cirsium | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | Carduus flodmanii, C. oblanceolatum | Carduus cymosus, C. botrys, C. triacanthum | ||||
Name authority | (Rydberg) Arthur: Torreya 12: 34. (1912) | (Greene) J. T. Howell: Amer. Midl. Naturalist 30: 37. (1943) | ||||
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