Biennial or perennial herbs, rarely annual. Stems winged or not. Hairs bristly, or soft and multicellular, or cobwebby. Lvs alternate, sessile, entire or pinnatifid or pinnatisect, dentate; lobes and teeth spine-tipped. Capitula homogamous, cylindric, ovoid or globose, solitary or in corymbs or clusters. Involucral bracts in several series, deltoid, lanceolate or linear; hairs cobwebby or 0; outer bracts usually spine-tipped, often spreading. Receptacle flat; scales numerous, setaceous. Florets ☿ or unisexual, all tubular. Corolla glabrous, 5-lobed, usually purple, sometimes white or yellow. Anthers acute at apex, with basal appendages 0.5-1.5 mm long; filaments ciliate. Style branches linear, erect, appressed. Achenes obovoid, weakly flattened, glabrous, smooth; achene insertion basal; pappus hairs in several rows, soft, silvery, plumose, united at base into a ring.