Description from Flora of China
Lianas. Leaves opposite, long petiolate. Cymes extra-axillary, pendulous, rachis laxly branched. Calyx with 5 glands at base. Corolla tube cylindric, with enlarged base, throat sometimes constricted; lobes patent, twisted to right. Corona lobes 5, adnate to base of staminal tube, margin and apex free, erect, oblong, obtuse, with ligulate inner lobes adnate to near apex, or corona lobes notched. Filaments connate into a tube; membranous anther appendages incurved; pollinia 2 per pollinarium, oblong, erect. Stigma head convex or conical. Follicles thick, acuminate, smooth. Seeds comose.
About ten species: Asia, tropical Africa, Oceania; three species in China.