Fl. W. Calif., 509. 1901.
Biennials, 5–400 cm; taproots. Stems usually 1, thinly to densely gray- or white-tomentose, sometimes ± glabrate; branches few–many, usually from above mid or near base in compact, moundlike dwarf plants, ascending to spreading. Leaves: blades oblong–elliptic to oblanceolate, 6–40 × 1.5–10+ cm, shallowly to deeply pinnatifid, lobes usually rigidly spreading, undivided or with 1–2 pairs of coarse teeth or lobes, main spines 5–15 mm, both faces gray- to white-tomentose, sometimes ± glabrate or adaxial faces green, thinly arachnoid-tomentose; basal sometimes present at flowering, petiolate or sessile and bases tapered, spiny-winged; principal cauline much reduced distally, sessile, bases decurrent or not, as spiny wings; distal much reduced, linear, ± bractlike. Heads 1–many in loose to tight clusters (barely raised above rosette in dwarf plants). Peduncles 1–30 cm. Involucres ovoid to spheric, 1.5–5 × 1.5–8 cm, arachnoid to ± loosely tomentose, often adjacent phyllaries connected by conspicuous arachnoid trichomes, sometimes glabrous or glabrate. Phyllaries in 7–10 series, subequal to strongly imbricate, green or stramineous to purple-tinged, linear to narrowly lanceolate, abaxial faces without glutinous ridge; outer and mid bodies appressed, entire, apices deflexed to spreading or ascending, short-triangular to elongate, linear-acicular, spines spreading to reflexed, 1–10+ mm; apices of inner erect, often flexuous, flat. Corollas white to lavender, pink, rose-purple, or red, 18–40 mm, tubes 8–18 mm, throats 5–7 mm, lobes 5–10 mm; style tips 4–5 mm. Cypselae ± brown, 5–6 mm, apical collars not differentiated; pappi 15–30 mm.
Calif., Nev., Oreg.
Varieties 7 (7 in the flora).
|1||Plants compact, rounded, moundlike; heads usually not much elevated above leaves||Cirsium occidentale var. compactum|
|1||Plants usually erect; principal heads usually conspicuously pedunculate||> 2|
|2||Corollas white to light purple or rose||Cirsium occidentale var. californicum|
|2||Corollas deep purple to bright pink or red||> 3|
|3||Plants densely white-tomentose; phyllaries persistently white-tomentose (except spines); outer phyllaries usually very long, spreading to reflexed||Cirsium occidentale var. candidissimum|
|3||Plants variably tomentose, sometimes ± glabrate; phyllaries ± arachnoid to floccose-tomentose, sometimes green and glabrate; outer phyllaries short to long, ascending to spreading or reflexed||> 4|
|4||Involucres usually about as long as wide or wider than long; phyllaries densely and persistently arachnoid with fine trichomes connecting tips of adjacent phyllaries||> 5|
|4||Involucres usually longer than wide; phyllaries tomentose or glabrate, sparingly or not arachnoid with fine trichomes connecting tips of adjacent phyllaries||> 6|
|5||Phyllary apices ± imbricate, the proximal usually shorter than medial and distal, lanceolate to linear-acicular, 0.5–15 mm; co- rollas bright purple||Cirsium occidentale var. occidentale|
|5||Phyllary apices subequal, all long- acicular, 1.5–3 cm; corollas light to deep reddish purple||Cirsium occidentale var. coulteri|
|6||Corollas 20–24 mm, deep reddish purple; s Santa Lucia Mountains of San Luis Obispo County, California||Cirsium occidentale var. lucianum|
|6||Corollas 23–35 mm, bright pink to red; widespread||Cirsium occidentale var. venustum|