Lianas, woody. Branchlets terete, slender, with conspicuous longitudinal ridges, glabrous. Leaves 3-foliolate; stipules caducous; petiole 5.5-7 cm; central petiolule ca. 2.5 cm, lateral petiolules 1-1.5 cm, glabrous; leaflets ovate-elliptic, 14.5-15.5 × 5.5-6 cm, glabrous, lateral veins 9 or 10 pairs, abaxially veinlets distinct but not raised, adaxially raised, base rounded, apex cuspidate. Compound dichasium, axillary, ca. 3 cm; peduncle ca. 1.7 cm, slightly papillose. Pedicel 1-1.5 mm, papillose. Buds ovoid-elliptic, 2-2.5 mm. Calyx cupular, papillose, teeth irregular. Petals elliptic, corniculate, glabrous. Filaments abortive and anther sterile in female flowers. Disk well developed in female flowers, undulately lobed. Lower part of ovary adnate to disk; style short; stigma 4-lobed. Fl. Jun.