Lianas, rarely shrubs. Leaves simple, opposite, papyraceous, chartaceous or coriaceous, entire; petioles sometimes with glands; stipules small, in pairs, single between the petioles, solitary at the base of the petiole or absent. Infiorescences axillary or terminal, generally cymose-paniculate, less frequently thyrsoid with flowers in terminal corymbs or umbels, sometimes simple umbels, corymbs or pseudoracemes; peduncles with 2 bracteoles at the apex or rarely lower on the peduncle; pedicels present and continuous with the peduncle; bracts and brac-teoles sometimes conspicuous. Flowers yellow; sepals 5, ovate or oblong, united at the base, usually 4 of them biglandular, rarely eglandular or all 5 sepals glan-dular; petals yellow, clawed, glabrous, the limb orbicular, ovate or elliptic, the margin entire, denticulate or weakly undulate; stamens 10, weakly unequal, the filaments united into a ring or tube at the base, glabrous or sometimes pilose, the anthers ellipsoid or oblong-ellipsoid, glabrous or rarely pilose; styles free, erect, thick, glabrous, generally 1 of the 3 thinner, the apex truncate; internal angle obtuse or at a right angle, stigmatic, the external angle obtuse, acute or apiculate, the ovary trilobate, velutinous-tomentose or hirsute. Fruit a schizocarp of 2 or 3 samaras, the mericarp with a narrow dorsal wing and 4 lateral wings, these forming an X as seen from above, rarely vestigial, sometimes with muricate or laminate appendages present between the dorsal and lateral wings; body smooth or coarsely veined, the ventral areole oval to suborbicular; cotyledons almost equal, folded.
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