Description from Flora of China
Herbs, annual or perennial, robust. Stems erect, branched. Leaves alternate, glabrous or pubescent, subentire, serrate, or pinnately lobed. Capitula disciform, heterogamous, in terminal paniculate corymbs, few calyculate. Involucres cylindric; phyllaries uniseriate, linear-lanceolate, equal, with scarious margins. Receptacle flat or slightly concave, alveolate or fimbriate. All florets tubular, fertile, outer florets biseriate or uniseriate, female, corolla filiform, 4- or 5-denticulate; central florets bisexual, funnelform, 5-denticulate. Anthers obtuse at base. Style branches elongate, apically truncate or obtuse, papillose. Achenes brownish, subcylindric, 10-ribbed. Pappus hairs many seriate, subequal, slender.
About five species: mainly in the Americas; two species (both introduced) in China.
(Authors: Chen Yilin (陈艺林 Chen Yi-ling); Bertil Nordenstam)