Perennial herb to 2 m tall. Stems stout, ridged, with cobwebby hairs. Rosettes tufted, withering at fruiting. Basal lvs deeply 1-2-pinnatifid, 30-60 × 15-35 cm; lobes narrow-lanceolate, becoming smaller towards the base, with sparse cobwebby hairs above and dense cobwebby hairs beneath, slightly viscid; midrib stout, ridged; spines borne on apices and clustered at bases of lobes, rigid, yellowish, 10-18 mm long. Stem lvs similar to basal, the upper becoming smaller and less divided. Capitula solitary or up to 7 in lax cymes, 5-10 cm diam. Involucre ovoid; outer bracts coriaceous, triangular, acute, recurved; middle bracts ovate, with a rigid, inrolled, narrow-triangular, erecto-patent, spinous appendage; inner bracts oblong to linear, with a scarious, triangular or ovate, cuspidate or mucronate, suberect appendage. Corolla 50-65 mm long; lobes blue, lilac or whitish. Style long-exserted, usually with a ring of short hairs at base of stigma branches. Achenes 6-9 × 3-5 mm, obovoid, pale, often with dark spots and streaks. Pappus 25-40 mm long.