Annual or biennial herbs. Stems erect, strongly branched, longitudinally striate; wings absent. Leaves broad, bipinnatifid to pinnatifid, with numerous spine-tipped lobes. Capitula pedunculate, homogamous. Involucral bracts spine-tipped or rarely unarmed; margins entire. Receptacle concave to convex, not alveolate, densely setose. Corolla purple or white; tube filiform; lobes linear. Anther filaments free, glandular. Style branches connate except near tip, erect. Achenes compressed-obovate, smooth or faintly ribbed, glabrous; apical rim indistinct; carpopodium basal. Pappus deciduous, of numerous plumose, capillary bristles, basally united in a ring.