Cirsium vulgare |
Cirsium flodmanii |
|
---|---|---|
bull or common or spear thistle, bull thistle, chardon vulgaire ou lancéolé, common thistle, gros chardon, piqueux, spear thistle |
chardon de Flodman, Flodman's thistle, prairie thistle |
|
Habit | Biennials, 30–200(–300) cm; taproots. | Perennials 30–140 cm; horizontal runner roots that produce root sprouts. |
Stems | 1–many, erect or ascending, branches few–many, ascending, villous with septate trichomes. |
1–several, erect, gray- or white-tomentose; branches 0–few, ascending. |
Leaves | blades oblong-lanceolate to obovate, 15–40 × 6–15 cm, margins plane or revolute, coarsely 1–2-pinnatifid with rigidly divergent lobes, sometimes merely spinose-dentate, lobes triangular to lanceolate, entire to spiny-dentate, main spines 2–10 mm, abaxial faces gray-tomentose, villous with septate trichomes along veins, adaxial green, covered with short appressed bristlelike spines, sometimes tomentose when young; basal present or absent at flowering, petioles winged, bases tapered; principal cauline winged-petiolate, mid and distal becoming sessile, well distributed or not, progressively reduced distally, at least distal decurrent as long spiny wings; distal cauline often more deeply lobed than proximal, main lobes rigidly spiny, margins spinulose, otherwise entire. |
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. |
Peduncles | 1–6 cm. |
0–5 cm (elevated above distal leaves). |
Involucres | hemispheric to campanulate, 3–4 × 2–4 cm, loosely arachnoid-tomentose. |
ovoid to broadly campanulate, 2–3.5 × 2.5–3.5 cm, thinly arachnoid. |
Corollas | purple (rarely white), 25–35 mm, tubes 18–25 mm, throats 5–6 mm, lobes 5–7 mm; style tips 3.5–6 mm. |
purple (white), 23–36 mm, tubes 12–15 mm, throats 6–8.5 mm, lobes 5–9 mm; style tips 4–7 mm. |
Phyllaries | in 10–12 series, strongly imbricate, linear-lanceolate (outer) to linear (inner), outer and middle appressed, (bases stramineous), margins entire, abaxial faces without glutinous ridge, apices radiating, greenish, spines 2–5 mm; apices of inner phyllaries flat, serrulate to minutely erose. |
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. |
Heads | few–many in corymbiform or paniculiform arrays. |
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). |
Cypselae | light brown with darker streaks, 3–4.5 mm, apical collar not differentiated; pappi 20–30 mm. |
light brown, 3–5 mm, apical collars stramineous, 0.5–1 mm; pappi (white or tawny) 20–30 mm. |
2n | = 68. |
= 22, 24. |
Cirsium vulgare |
Cirsium flodmanii |
|
Phenology | Flowering mostly summer (Jun–Sep), year round in areas with mild climates. | Flowering summer (Jun–Sep). |
Habitat | Invasive weed of disturbed sites, pastures, meadows, forest openings, roadsides | Tallgrass, mixedgrass, shortgrass prairies, meadows, pastures, often in damp soil |
Elevation | 0–2200 m (0–7200 ft) | 100–2400 m (300–7900 ft) |
Distribution |
AK; AL; AR; AZ; CA; CO; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; NC; ND; NE; NH; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; SD; TN; TX; UT; VA; VT; WA; WI; WV; WY; AB; BC; MB; NB; NF; NS; ON; PE; QC; SK; SPM; Eurasia [Introduced in North America]
|
CO; IA; IL; KS; MI; MN; MT; ND; NE; SD; WI; WY; AB; MB; ON; QC; SK
|
Discussion | Native to Eurasia, Cirsium vulgare is the only thistle in North America with bristlelike spines borne on the adaxial leaf faces. These structures are variously described in the literature as trichomes (“spreading hirsute,” “scabrous-hispid,” “coarsely hispid,” “rigid, rather pungent setae,” “prickly-hairy”), prickles, or spines (“setose-spinulose,” “appressed and dense spines”). My examination of cleared leaves of C. vulgare indicated that these structures are not epidermal outgrowths (trichomes or prickles) but emerge from fine veinlets within the tissues of the leaf. As such, they are properly treated as spines. Bull thistle is a noxious weed that has invaded disturbed habitats across the continent. Distasteful to livestock, it can increase in heavily grazed pastures. It occurs in a wide variety of habitats. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
Source | FNA vol. 19, p. 109. | FNA vol. 19, p. 120. |
Parent taxa | Asteraceae > tribe Cardueae > Cirsium | Asteraceae > tribe Cardueae > Cirsium |
Sibling taxa | ||
Synonyms | Carduus vulgaris, Carduus lanceolatus | Carduus flodmanii, C. oblanceolatum |
Name authority | (Savi) Tenore: Fl. Napol. 5: 209. (1835) | (Rydberg) Arthur: Torreya 12: 34. (1912) |
Web links |
|