E-Flora BC: Electronic Atlas of the Flora of British Columbia

General:
Biennial herb; stems spiny-winged, branched above, 0.3-1.5 m tall.

Leaves:
Basal leaves lacking; stem leaves narrowly elliptic or oblong in outline, deeply lobed or pinnately cut, up to 25 cm long and 8 cm wide, sparsely hairy on main veins, spiny-margined.

Flowers:
Heads discoid, 1.5-2.5 cm wide, clustered or solitary and erect at the ends of branches; involucres hemispheric; involucral bracts linear-lanceolate, in 2-3 series, somewhat leafy and spreading, outer ones spine-tipped; disk flowers usually purplish, sometimes cream or white, nearly 2 cm long.

Fruits:
Achenes glabrous, egg-shaped, with 15-20 dark longitudinal lines and a lighter collar at the tip; pappus whitish with minutely finely-barbed bristles.