Herbs, perennial, 1-1.8 m tall. Taproots columnar, slightly fleshy. Stems erect, 6-8-ridged, ridges sparsely covered with retrorse spines. Basal leaves rosulate; petiole up to 30 cm; leaf blade broadly lanceolate, 10-18 × 6-12 cm, pinnatifid or pinnatisect; segments 5-7; terminal segment larger, oblong or broadly ovate, 6-12 × 4-8 cm; lateral ones smaller downward, lanceolate to ovate; all segments abaxially glabrous, adaxially puberulent or glabrous. Lower and middle cauline leaves shorter petiolate; leaf blade pinnatisect; terminal segment larger; lateral segments 2- or 3-paired, ovate to lanceolate; upper cauline leaves undivided or 3-segmented, segments lanceolate, both surfaces glabrous, sometimes adaxially sparsely white puberulent, margins entire. Heads globose, 2-2.5 cm in diam.; peduncles up to 30 cm; involucral bracts 7 or 8, leaflike, lanceolate, white puberulent; bracts oblong-obovate, 6-8 mm, rostrum 1-3 mm, glabrous, sparsely setose, or villous basally; involucels obovoid-columnar; limb 4-lobed; lobes acute at apex. Calyx disk-shaped, 4-angular, outside glabrous, inside and apex villous. Corolla black-purple; tube 6-7 mm, base narrowly tubular, 1-1.5 mm; limb with one larger lobe. Stamens strongly exserted. Achenes pale brown, 2.5-4 mm, 4-angular, cuneate. Fl. Jul-Sep, fr. Sep-Nov.