Scarcely scented, perennial herb. Stems erect, up to c. 1 m tall, glabrous or with a few scattered hairs, striate, simple or branched at base or above. Basal and lower cauline lvs petiolate, narrow-elliptic, acute to obtuse at apex, cuneate, evenly 1-serrate, glabrous, up to c. 30 × 4 cm; cauline lvs similar to basal but above becoming smaller, apetiolate, amplexicaul, the uppermost lanceolate to linear and sometimes almost entire. Involucral bracts 6-12 mm long, glabrous; margins and apex brown, membranous; inner bracts at least with extended apical flap. Capitula solitary, (50)-70-120 mm diam.; ray florets 20-40; ligules white; disc florets numerous, yellow. Achenes 2.5-4 mm long, dark brown with paler ribs; achenes of disc florets ± terete or somewhat flattened, with 10 ± equal ribs, and corona 0; achenes of ray florets similar to those of disc florets but with lateral ribs sometimes somewhat thicker, and an irregular corona up to c. 1 mm long.