Perennial subshrubs, shrubs or trees, often resinous, rarely rhizomatous; stems often striate or angled, glabrous, glabrescent, hispidulous or villous. Leaves sessile or petiolate, alternate, 1- or 3-nerved, entire to coarsely serrate, often gland-dotted. Capitula unisexual, sessile or pedunculate, discoid, usually in panicles or corymbs, sometimes in racemes or solitary; involucral bracts 2–5 seriate, imbricate, unequal, herbaceous with scarious, erose or ciliate margins; receptacle flat to conical, pitted or smooth, usually naked. Florets of female capitulum filiform to tubular; corolla 5-lobed, whitish; style branches glabrescent, appendages absent. Florets of male capitula tubular; corolla 5-lobed; anthers obtuse at base; ovary abortive; style present. Cypselas obovoid to cylindric, ± compressed, 5–10 nerved, glabrous or hispid; pappus persistent or deciduous minutely barbellate bristles, those of male florets shorter, fewer, usually dilated or plumose at apex.
c. 400 species native to North, Central and South America; 2 species naturalised in Australia.