Mostly climbing, occasionally erect, shrubs and undershrubs; often prickly. Leaves alternate, usually entire, 3-5-nerved; nerves convergent, veins reticulate. Flowers small, dioecious, bracteolate or not. Perianth segments 6, in 2 series, free. Male flower: stamens 6, anthers didymous, pistillodes absent. Female flower: staminodes 3 or 6, stigmas sessile, recurved. Fruit 3-locular. Seeds ellipsoid.