Tall unarmed lianes; older stems subterete, weakly grooved. Latex absent. Leaves opposite or slightly subopposite; blade entire to shallowly dentate. Stipules minute, free, inserted at the nodes. Inflorescences of axillary dichotomous cymes with equal branches and a terminal flower at each fork. Flowers small, pedicellate, congested; young buds globose. Sepals 5, imbricate. Petals 5, not spreading but rather arcuate, 4 of them ± equally arched giving the flower a somewhat zygomorphic appearance. Disc divided into 3 crescent-shaped substaminal lobes, each of which enfolds a stamen. Stamens 3, with very short, broad filaments; anthers extrorse, dehiscing by a transverse slit; pollen small, simple, tricolporate. Ovary with 3 locules, each with 2 ovules; stigmas 3, sessile, together forming a ± triangular organ which exceeds the stamens, each stigma curved down over an anther. Fruit of 3 flattened mericarps each of which dehisces by median sutures into 2 caducous valves. Seeds 2 in each mericarp, winged, the wing with a marginal vein and a submedian vein (the raphe); cotyledons not united; radicle acute and prominent. Germination epigeal.
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