Non-stoloniferous, annual, biennial or (not in Australia) perennial herbs, with eglandular cottony hairs. Leaves alternate, sometimes rosetted at base, sessile, entire. Capitula c. ovoid to campanulate, in head-like clusters or in more or less elongated spikes. Involucral bracts in 3–5 series, increasing in length from outer to inner, the outer part papery, translucent (brownish to reddish), and partly hyaline. Florets all tubular, the outer filiform, female, purple, with 3- or 4-lobed corollas; inner florets bisexual, fewer than female florets, with purple, 5-lobed corollas, anthers shortly tailed; style branches linear, apices truncate. Cypselas flattened-ellipsoid, with small, globose, mucilage-producing hairs; epidermis smooth; pappus hairs barbellate, united at base and falling as a unit.
About 50 species, largely confined to the Americas (mainly South America); 2–5 species naturalised in Australia.