Perennial herbs or subshrubs, scabrous or sometimes strigose-hirsute; stems creeping or scandent, elongate. Leaves opposite. Heads radiate, terminal or axillary, pedunculate, heterogamous. Involucre subglobose, bracts in 1 series, outer ones green or foliaceous, coarsely strigose, inner ones dry. Receptacle flat or convex, paleae convex, enclosing florets. Ray florets ligulate, fertile, corolla spreading, entire or 2-toothed, yellow. Disc corollas tubular, limb elongate, 5-lobed; anthers appendaged at apex, entire or nearly so at base; style branches of disc florets acute, hairy abaxially; achenes oblong-cuneate or obovate, thick, flattened laterally (trigonous in ray achenes). Pappus absent or crown-like, toothed or ringed, or consisting of 1 or 2 small, short, deciduous bristles.
Pantropical, ca. 100 species; in Taiwan, four species, two of which are represented by two varieties each.