Description from Flora of China
Lianas or erect or stolon-bearing shrubs, rarely trees, with latex. Leaves opposite or in whorls of 3. Cymes mostly dichasial, terminal, pedunculate or sessile. Flowers large. Sepals free or connate at base, imbricate or quincuncial, basal glands 5 to many. Corolla funnelform, usually turning darker and dark streaked at anthesis; tube short, throat wide; lobes overlapping and mostly twisted to right, distal portions mostly forming filiform, involute long tails; corona 10-lobed, inserted at base of corolla lobes. Stamens inserted at apex of corolla tube; filaments short; anthers sagittate, connivent, adherent to pistil head, spurred at base; disc absent. Ovaries 2, ± connate at base; ovules numerous in each locule. Style filiform. Follicles 2, divaricate. Seeds numerous, with beaked apical coma.
Thirty-eight species: tropical Africa, Asia; six species in China.