Trees. Leaves cordate, usually entire, but lobed when very young. Inflorescence axillary, racemose or paniculate. Flowers unisexual. Calyx campanulate, 5-lobed to base, lobes reflexed at apex. Petals absent. Male flowers: androgynophore cylindrical, enclosed by calyx, apex cup-shaped. Filaments clustered into 5 groups, staminodes usually present; anthers sessile. Female flowers: androgynophore very short, with 5 undeveloped staminodes. Carpels almost free; ovules many per carpel; stigma swollen, radiate. Follicle woody, subglobose, with long stipe and many seeds. Seeds with long and wide apical wing.

About 20 species: African and Asian tropics; one species in China.