Liana; stems short-pilose. Leaves trifoliolate; stipules subulate, to 1.5 cm long, subpersistent; petioles usually 3-5 cm long (to 12 cm on juvenile leaves), the pulvinus terete, basal; rachis usually ca 2 cm long (to 4.5 cm on juvenile leaves); stipels acicular, 5-15 mm long; petiolules 5-10 mm long, swollen; leaflets broadly elliptic, acuminate, rounded to somewhat cordate at base, 7-11 cm long, 4-7 cm wide, sparsely appressed-pilose all over or glabrate above except on midrib (young leaves sericeous above). Racemes long-stalked, to 50 cm long; rachises studded with tuberculate knobs on which the flowers develop; pedicels 2-4 mm long at anthesis, enlarging in fruit; calyx 10-12 mm long, lobed, the lobes 4, acuminate, spreading; standard, wings, and tip of keel violet; standard rounded, 16-20 mm wide, emarginate, reflexed, with a small yellow guide spot at base in center; wings ca 17 mm long, erect, joined to keel near base, the keel weakly fused apically; stamens and style curved upward near apex, equal in length, the free stamen and alternate stamens of the staminal tube somewhat shorter than the others; anthers and style fully exposed to a pollinator approaching the nectary from the base of the standard; pollen tacky, adhering to anther after dehiscing; nectary prominently raised. Legumes densely pubescent (less so at maturity), 7-10 cm long, ca 14 mm wide, the upper margin with sharp lateral ribs; segments 8-10. Croat 4841. Infrequent, along the shore and in clearings, especially the Lighthouse Clearing. Probably more abundant in earlier years, since it grows in weedier areas in other parts of the Canal Zone. Flowers mostly throughout the dry season (December to April). The fruits mature mostly in the late dry and early rainy seasons (March to May). Panama to northern South America. In Panama, known from tropical moist forest in the Canal Zone, Colón, Coclé, Panama, and Darien, from tropical dry forest in Coclé, from premontane moist forest in the Canal Zone, and from premontane wet forest in Chiriqui.