Perennial, erect herbs; stems leafy. Leaves opposite, often petiolate, usually serrate. Heads small, in loose corymbs, pedunculate. Involucres subglobose, bracts herbaceous, in 2 series, equal, free of connate at base. Receptacles flat, alveolate, homogamous. Florets tubular, bisexual, fertile, corollas 4- or 5-toothed. Anthers obtuse at apex, base obtuse to subtruncate. Styles long-exserted, arms elongate, flat, obtuse. Achenes obtusely 3-angled, glandular dotted or tuberculate, rounded at apex. Pappus of 3 or 4 clavate gland-tipped bristles.
About 24 species in Central and South America and Australia to tropical and temperate Asia; one species represented by two varieties in Taiwan.
