Perennial herb 1-(2) m tall. Stems stout, ridged, with cobwebby hairs. Rosettes tufted, withering at fruiting. Basal lvs deeply pinnatifid, 30-60 × 15-40 cm; lobes lanceolate, becoming smaller towards base, glabrescent above, with cobwebby hairs beneath, viscid; midrib stout, ridged; spines usually 0 or sometimes fine, marginal, 2-3 mm long. Stem lvs similar to basal, the upper becoming smaller and less deeply divided. Capitula usually solitary, (7)-8-12 cm diam. Involucre globose to hemispheric; outer and middle bracts fleshy, ovate, with a suberect, emarginate-mucronate or cuspidate appendage; inner bracts oblong, with a scarious, ovate to lanceolate, mucronate appendage. Corolla 50-65 mm long; lobes lilac or blue. Style long-exserted, with base of stigma branches glabrous. Achenes 6-9 × 3-5 mm, obovoid, pale, usually spotted. Pappus 30-50 mm long.