Dioecious shrubs or perennial herbs. Lvs alternate, simple, entire, serrate or lobed. Capitula in small terminal or axillary glomerules. Involucral bracts in 3-many rows, imbricate, ± membranous. Receptacle flat or convex; scales 0. ♀ florets filiform, numerous. ♂ florets tubular, numerous. Achenes all similar, ellipsoid or obovoid, compressed or terete, ribbed; pappus of hairs in 1 row, that of sterile ♂ florets shorter.