© Thayne Tuason (Photo ID #76403)
Biennial herb from a fibrous root; stems erect, simple, branched, broadly spiny-winged, woolly-hairy, 1.5-3.0 m tall.
Basal leaves lacking; stem leaves alternate; lower leaves elliptic to oblanceolate, toothed to deeply pinnately-lobed, 10-60 cm long, 5-10 cm wide, spiny, the spines 2-5 mm long, sparsely woolly-hairy and green above, densely white woolly-hairy below; upper leaves reduced and linear-elliptic to linear-lanceolate.
Heads discoid, few to many at the ends of branches; involucres egg-shaped to more or less rounded, 2.5-3.5 cm tall; involucral bracts lanceolate, tapering to a stiff, spreading spine 4-5 mm long, outer ones 2 mm wide at the base, inner ones similar but more flexible, flatter, and with shorter spines; disk flowers reddish-purple; receptacles flat, fleshy, honeycombed, often with short bristles on the partitions.
Achenes hairy, transversely wrinkled, greyish-brown, 4-5 mm long; pappus of numerous slender bristles.