Description from Flora of China
Trees or robust erect shrubs, latex present, branches dichotomous. Leaves opposite; petioles or leaf bases of a node often connate into a short ocrea, with a single row of colleters in axils. Cymes terminal, pedunculate. Flowers often fragrant. Calyx campanulate to cylindric, with many basal glands inside. Corolla white or yellow, salverform, large, tube widened at base and at or above middle, shorter or only slightly longer than calyx, throat with a fleshy ring, not scaly, lobes spreading or recurved, overlapping to left. Stamens inserted in distal widening of corolla tube, exserted or included; anthers sessile, sagittate, coherent to pistil head; disc ringlike or of five lobes adnate to ovaries. Ovaries 2, free or fused basally; ovules numerous. Pistil head lampshade-shaped, apex shortly 2-cleft. Follicles 2, pendulous. Seeds numerous, embedded in pulp, not comose.
Twelve species: seven in Africa, five in SE Asia; two species cultivated in China.