Annual herbs, 10-40 dm tall; stems simple below, branching above, tomentose when young, the tomentum becoming floccose with age. Lower leaves to 45 cm long and 18 cm wide, the sinus depth to 95% of the leaf width; upper leaves to 10 cm long and 6 cm wide, the sinus depth variable and less than in the lower leaves; leaf bases decurrent, the wings to 5 cm long, tomentose beneath, glabrous above or with a thin tomentum along the major veins, the marginal spines 6-12 mm long, usually longest on decurrent wings. Inflorescence of terminal clusters of 3-5 or single heads on short peduncles arising from the axils of the upper and middle cauline leaves. Heads with the involucre 8-or 9-seriate, 3-3.5 cm tall, 1.5-2 cm in diam. at the base, the outer involucral bracts 4-6 mm long, basally 1-2 mm wide, with a glutinous dorsal ridge, tapering to a 5-7 mm long spine, the innermost bracts 25-35 mm long, 1-2 mm wide, tapering, twisted and often purple near the tip; corolla purple to reddish, 26-30 mm long, the lobes 4-5 mm long, the anthers colorless, 4-5 mm long, the style purple 27-31 mm long, the branches 2-3 mm long. Achenes 4-5 mm long, 1-1.5 mm in diam.; pappus 23-25 mm long.
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