Twining herbs, branches pubescent, hispid or prickly. Leaves opposite, cordate, temontose on both sides. Flowers in umbelloid to racemoid cymes, solitary at nodes. Calyx lobes 5, ovate-lanceolate, acute. Corolla yellowish or greenish white, campanulate lobes imbricate in bud. Corona in 2 series, the outer glabrous, a 5-lobed annulus at the base of the staminal column; the inner of 5 fleshy lobes, each with 2 spurs, one directed outward and downward and the other upward with the tip over the gynostegium. Anthers with prolonged membranous connectives. Pollinium solitary in each loculus, pendulous, hyaline margin narrow. Follicles lanceolate, usually echinate. Seeds comose.