Shrub ca. 2 m tall in juvenile stages, or liana 5-10 m long when mature. Stems terete, finely striate, lenticellate, ferruginous-tomentulose to tomentose, glabrescent, producing scarce or abundant milky latex; cross section with a single vascular cylinder. Stipules oblong, concave, clasping the stem, 2-4 cm long, deciduous, leaving a scar to 5 mm wide. Leaves 7(9)-pinnately compound, the lower pair of pinnae trifoliolate; petioles and rachis broadly winged, marginate or less often unwinged, petiole 5.5-19 cm long, rachides much shorter than the petiole; leaflets chartaceous to coriaceous, glabrous, oblong, elliptic or oblanceolate, 4.5-20 × 2.5-7.6 cm, the base attenuate on distal leaflets, abruptly acuminate on medial ones and obtuse on basal ones, the apex acuminate to cuspidate, the margins remotely serrate on upper half of blade or less often subentire; tertiary veins clathrate or nearly so. Thyrses paniculate or racemiform, densely flowered, ferruginous-tomentulose; bracts and bracteoles deltate, ca. 1 mm long, sericeous-pubescent; cincinni sessile or stipitate, distal ones often sessile, while proximal ones stipitate. Calyx flavo-sericeous, greenish white, sepals 4, concave, outer sepals rounded, ca. 2 mm long, inner sepals oblong, rounded at apex, 4-5 mm long, the anterior inner sepal (representing two connate sepals) sometimes notched at apex; petals white, oblong, ca. 5 mm long, rounded at apex, adaxially sparsely papillate; appendages hood-shaped, nearly as long as the petals, with a fleshy, yellow crest at the apex and appressed-pubescent margins; disc glabrous, of 2 large, oblong posterior lobes and 2 obsolete, lateral ones; filaments entirely appressed-pubescent. Capsule globose or trigonous-globose, unwinged, yellow, flavo-velutinous, woody, 1-seeded, (3) 6-9-ridged, long-stipitate, apiculate at apex, the coccus 1-2 cm long, the stipe 1-2.2 cm long; pericarp ca. 2 mm thick; endocarp papery, pruinose; seed subglobosewith a sarcotesta except for a rounded ventral area.