Cirsium horridulum |
Cirsium wheeleri |
|||||||||
---|---|---|---|---|---|---|---|---|---|---|
bristly or horrid or yellow or bull thistle, bristly thistle, bull thistle, horrid thistle, yellow thistle |
Wheeler's thistle |
|||||||||
Habit | Biennials or perennials, (± fleshy), 15–250 cm; stout taproots and a fascicle of fleshy lateral roots, often perennating by root sprouts. | Perennials, slender, 15–60 cm; taprooted with deep-seated root sprouts. | ||||||||
Stems | 1–several, usually erect, often stout, glabrous to densely tomentose; branches 0–many, spreading to ascending, short, stout. |
1–few, erect, closely gray-tomentose; branches 0–few, ascending. |
||||||||
Leaves | blades linear to oblanceolate or oblong-elliptic, 10–40 × 2–10 cm, unlobed and spiny-dentate to deeply pinnatifid, lobes spiny-dentate or coarsely lobed, main spines stout, 5–30 mm, abaxial faces subglabrous to loosely tomentose, adaxial glabrous to ± densely villous with septate trichomes; basal present at flowering, spiny winged-petiolate, bases often tapered; principal cauline sessile, well distributed, often not much reduced distally, bases often ± auriculate-clasping; distal cauline often spinier than the proximal. |
blades lanceolate to narrowly elliptic, 10–25 × 1–4 cm, unlobed and merely spinulose or pinnately lobed about halfway to midveins, often terminal lobes long-tapered, lobes short, lanceolate to triangular, entire to few toothed or lobed, well separated by wide, U-shaped sinuses, main spines slender, 2–5 mm, abaxial faces gray-tomentose, adaxial green, glabrous to thinly tomentose; basal usually present at flowering, winged-petiolate; principal cauline winged-petiolate proximally, mid and distal sessile, progressively reduced distally, bases not or scarcely decurrent, sometimes distal weakly clasping; distalmost often reduced to lanceolate or linear, long-acuminate bracts. |
||||||||
Peduncles | 0–5 cm. |
0–10 cm. |
||||||||
Involucres | hemispheric to campanulate, 3–5 × 3–8 cm. |
hemispheric to subcylindric, 1.5–2.2 × 1.5–2.5 cm, thinly floccose-tomentose or glabrate. |
||||||||
Corollas | white to yellow, pink, purple, or red, 30–47 mm, tubes 11–30 mm, throats 6–10 mm, lobes 7–10 mm; style tips 3–5 mm. |
white or pink to pale purple, 20–28 mm, tubes 9–14 mm, throats 5–7.5 mm, lobes 5–10 mm; style tips 2.5–6 mm. |
||||||||
Phyllaries | in 5–9 series, subequal to imbricate, light green to stramineous, lanceolate to linear, distally often with reddish margins, abaxial faces without glutinous ridge, often ± thinly tomentose, often scabridulous in submarginal bands; outer and middle appressed-ascending, bodies usually reddish-tinged, margins setulose-ciliolate, apices acuminate, spines 1–2 mm, weak; apices of inner straight, flat. |
in 6–9 series, imbricate, pale green with darker apices, brownish when dry, lanceolate (outer) to linear-lanceolate (inner), margins of outer entire, abaxial faces with narrow glutinous ridge; outer and middle appressed proximally, apices spreading to ascending, bodies entire or rarely spinulose, spines slender, 3–7 mm; apices of inner often dark purple or blackish, flexuous, scarious, entire to pectinate-fringed, tapered or expanded. |
||||||||
Heads | 1–20 in subcapitate to corymbiform arrays (each closely subtended by an involucre-like ring of spiny-margined bracts). |
1–6, borne singly or few at branch tips in corymbiform arrays. |
||||||||
Cypselae | straw-colored to tan, 4–6 mm, apical collars weakly differentiated; pappi 25–35 mm. |
stramineous with brownish streaks, 6.5–7 mm, apical collars colored like body, narrow; pappi 15–20 mm. |
||||||||
2n | = 32, 33, 34, 35. |
= 28. |
||||||||
Cirsium horridulum |
Cirsium wheeleri |
|||||||||
Phenology | Flowering summer–fall (Jul–Oct). | |||||||||
Habitat | Coniferous forests, pine-oak, juniper-dominated woodlands, meadows | |||||||||
Elevation | 1200–2900 m (3900–9500 ft) | |||||||||
Distribution |
AL; AR; CT; DE; FL; GA; LA; MA; MD; ME; MS; NC; NH; NJ; NY; OK; PA; RI; SC; TN; TX; VA; Mexico
|
AZ; CO; NM; TX; UT; Mexico (Chihuahua, Sonora)
|
||||||||
Discussion | Varieties 4 (3 in the flora). Although several variants have been given taxonomic recognition as species, these seem at most races. Flower color varies greatly, sometimes within populations and sometimes on a populational or regional basis. Herbarium specimens are sometimes difficult to assign to variety. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Cirsium wheeleri occurs from the mountains of the Colorado Plateau of central Utah and southwestern Colorado south through the highlands of Arizona and New Mexico to southwestern Texas and northwestern Mexico. The recently described C. wheeleri var. salinense is a minor variant with subentire leaves that is scattered through much of the range of the species. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
||||||||
Key |
|
|||||||||
Source | FNA vol. 19, p. 114. | FNA vol. 19, p. 125. | ||||||||
Parent taxa | Asteraceae > tribe Cardueae > Cirsium | Asteraceae > tribe Cardueae > Cirsium | ||||||||
Sibling taxa | ||||||||||
Subordinate taxa | ||||||||||
Synonyms | Cnicus wheeleri, C. blumeri, C. olivescens, C. perennans, C. wheeleri var. salinense | |||||||||
Name authority | Michaux: Fl. Bor.-Amer. 2: 90. (1803) | (A. Gray) Petrak: Bot. Tidsskr. 31: 67. (1911) | ||||||||
Web links |