Description from Flora of China
Lianas woody, latex white. Leaves opposite. Cymes racemose or paniculate, 3-5-branched, terminal or axillary. Flowers usually small, 5-merous. Calyx deeply divided, with many basal glands inside. Corolla salverform, tube cylindric, throat narrowed, without scales, lobes overlapping to right. Stamens inserted at apex of corolla tube; filaments short; anthers exserted, sagittate, connivent at middle, adherent to pistil head, cells spurred at base; disc 5-parted. Ovaries 2, free, shorter than disc; ovules numerous in each ovary. Style thickened at middle or near base; pistil head ovoid or fusiform, apex short conical. Follicles 2, elongated, linear. Seeds linear, elongated, not beaked, apex comose; endosperm copious; cotyledons linear, flat, radicle superior.
About four species: SE Asia, two species in China.