Cirsium occidentale (Nutt.) Jeps.
Family: Asteraceae
Cobwebby Thistle
Cirsium occidentale image
Gerald and Buff Corsi  

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.

Cirsium occidentale image
Gerald and Buff Corsi  
Cirsium occidentale image
Gladys Lucille Smith  
Cirsium occidentale image
Charles Webber  
Cirsium occidentale image
Beatrice F. Howitt  
Cirsium occidentale image
Gladys Lucille Smith  
Cirsium occidentale image
Gerald and Buff Corsi  
Cirsium occidentale image
Gerald and Buff Corsi  
Cirsium occidentale image
George G. Hawxhurst  
Cirsium occidentale image
Beatrice F. Howitt  
Cirsium occidentale image
Beatrice F. Howitt  
Cirsium occidentale image
Barry Breckling  
Cirsium occidentale image
Keir Morse  
Cirsium occidentale image
Keir Morse  
Cirsium occidentale image
Keir Morse  
Cirsium occidentale image
Keir Morse  
Cirsium occidentale image
Keir Morse  
Cirsium occidentale image
Keir Morse  
Cirsium occidentale image
J. E.(Jed) and Bonnie McClellan  
Cirsium occidentale image
Charles Webber  
Cirsium occidentale image
Jo-Ann Ordano  
Cirsium occidentale image
Keil, David