Woody vine or liana > 10 m long. Stems pentagonous, glabrous, reaching 3 cm in diam. at base, producing abundant milky sap; cross section with a single vascular cylinder, usually with hollow pith. Stipules deltoid, minute. Leaves biternate (sometimes trifoliolate); petiole and rachis furrowed, stout, glabrous; petiolules and secondary petioles reddish tinged; leaflets chartaceous, glabrous, elliptic, 5-15 × 3-7 cm, the base attenuate or acute on distal leaflets, obtuse to nearly rounded on lateral ones, the apex cuspidate to caudate, the margins entire or repando-dentate. Thyrses axillary, paniculate, up to 35 cm long, with glabrous axes; cincinni alternate, shortly stipitate, tomentulose; bracts and bracteoles ovate-deltate, ca. 0.5 mm long. Flowers 5-6 per cincinni; pedicels tomentulose, 3-4 mm long, articulate at the middle; sepals 5, whitish, rounded at apex, the outer ones ovate, ca. 2 mm long, tomentulose to nearly glabrous, the inner ones oblong, ca. 3 mm long, tomentulose; petals white, widely spatulate, ca. 3.5 mm long, adaxially papillate; appendages with fleshy, yellow crest; disc glabrous, with 2 posterior deltoid, fleshy lobes ca. 1 mm tall, and 2 smaller, rounded lateral ones; stamens sparsely pubescent, the anthers pinkish; gynoecium glabrous. Mericarps glabrous, 4-6 cm long, the wings reddish tinged, the cocci divaricate, ovoid, 5-6 mm tall, with prominent reticulate venation.
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