Fls nectariferous, subsessile, bracted, in dense heads subtended by foliaceous bracts. Calyx-teeth prominent, persistent, rigid; petals notched, inflexed. Fr. ovoid to obovoid, covered in tubercles or scales; vittae 5; commissure broad; mericarps obscurely ribbed. Perennial herbs with mainly radical lvs; teeth us. pungent. Widespread genus of some 220 spp.; the N.Z. sp. also in Tasmania and Australia.

Glabrous annual, biennial or perennial herbs. Lvs simple, entire, pinnate or palmately lobed, usually spinous. Fls sessile in capitula, these solitary or in cymes or racemes; bracts in one or more series subtending the head, usually spinous; bracteoles subtending fls usually spinous, entire or 3-fid. Petals white to purple or greenish, regular, variously lobed or fringed, inflexed; calyx teeth evident, usually acute, rarely spinescent, > petals. Fr. ovoid to subglobose, scarcely flattened laterally, variously covered with scales, spines or tubercles; commissure broad; ribs obscure; vittae usually solitary.