Annual or perennial herbs, sometimes rooting at the nodes. Stem 1–many, branched from the base. Leaves ovate or elliptic, opposite or basally rosulate, petiolate. Capitula solitary or few, on axillary or terminal peduncles, sometimes arranged in cymes, radiate, disciform or discoid. Involucres more or less hemispherical to ovoid. Phyllaries 1–3–seriate, outer spreading and longer, entire or irregularly dentate. Receptacle conical, paleate, paleae membranous, loosely enfolding cypsela and falling together. Ray florets usually present, 1–seriate, female, purplish to yellow – orange or white, 2– or 3–lobed, sometimes absent. Disc florets yellow or orange, 4– or 5–lobed, bisexual, fertile. Ray cypselas triquetrous, obovoid to ellipsoid, ± glabrous to densely pubescent, brown, disc cypselas compressed, obovoid to ellipsoid, sometimes with corky margins, pappus absent or of upto 10 soft bristles.
A genus of about 30 species, distributed mainly in new world tropics, few species are pantropical, two species are cultivated in Pakistan.