Climbers [rarely trees], with simple hairs. Inflorescences leaf-opposed, extra-axillary, or superaxillary, 1-flowered, bracteate. Flowers (not known for only Chinese species) bisexual. Sepals 3, valvate, ± connate at base. Petals 6, in 2 whorls, free, valvate; outer petals flat or 3-ridged, long and narrow, leathery, basally broadened and concave; inner petals much shorter than outer, ovate, lanceolate, or oblong, narrowed at base and often with a gap between petals, cohering to cover stamens and carpels. Stamens many; connectives apically enlarged and concealing anther locules, apex truncate. Carpels many, oblong; ovules 1-5 per carpel, lateral; styles clavate. Fruit apocarpous; monocarps stipitate, subglobose [or globose to ellipsoid-cylindric], moniliform when more than 1-seeded; epicarp thin to thick. Seed usually 1 per monocarp, subglobose.
Seeds similarly shaped, smooth; testal intrusions into the endosperm lamelliform.
Stamens numerous to very numerous, forming a hemispherical or subglabose androecium; filaments usually short; connective-appendages flattened and covering the anther-cells, nearly always hiding them and typically forming a flat tight pavement
Petals 6, valvate, typically very unequal, the outer large and elongate, the inner much smaller, ovate-lanceolate or oblong, connivent over the stamens and ovaries with margins adhering, but in African species the petals are often much less unequal and the inner ones scarcely connivent
Monocarps with 1 article or up to 5 in African species; articles cylindric, ellipsoid or sausage-shaped
Carpels usually numerous, oblong or cylindric, with 1 (rarely 2) ovules in Asiatic species but 1–5 in African species; style distinct; stigma capitate or clavate, grooved
Typically woody climbers or in Africa often shrubs, glabrous or with an indumentum of simple or rarely (in the single East African species) with forked or ± stellate hairs
Flowers hermaphrodite, solitary, fascicled or in cymes, typically extra-axillary; bracts and bracteoles sometimes developed