Tendriled liana; trunk to 40 cm diam near the ground; larger stems with densely and minutely fissured, rusty-brown outer bark; smaller stems green, shiny, almost glabrous. Leaves bipinnate with usually 2 pairs of pinnae, the pinnae opposite, each 6-10 cm long; rachis 6-12 cm long, ending with a simple tendril to 15 cm long; petiolules short, with prominent basal pulvinus; leaflets in (3) 5 (6) pairs per pinna, asymmetrically oblong, blunt to emarginate at apex, unequal at base, mostly 2.5-5 (7) cm long, 1.2-3 cm wide, glossy above, dull below; midrib puberulent. Inflorescences densely flowered, slender, spikelike racemes inserted shortly above leaf axils, to 25 cm long; flowers green, with a strong and sweet but disagreeable odor, maturing from base of rachis upward; pedicels short; calyx cupulate, about 1 mm long, the lobes minute; petals elliptic, ca 3 mm long and 1 mm wide, the margins sometimes scarious; stamens 10, ca 6 mm long; filaments white, the connective bearing a minute, stalked, papillate food body at apex. Legumes very large, 30-120 cm long, 10-13 cm wide, forming a broad spiral, the margins raised; seeds button-shaped, 5-6 cm diam, to 2 cm thick, dark and shiny at maturity. Croat 4957, 7869. Occasional, in the canopy of the forest and pendent from the trees on the lakeshore. Seasonal behavior uncertain. Flowers from November to May. The fruits reach mature size by the late rainy season, but it is not known when they are dispersed, perhaps during the dry season. Recognized by the huge fruits, which require about a year to mature. Seeds either are removed from the stout valves by animals, which tear holes in the valves, or fall from the weathered valves. The species is common in riparian situations, and water is known to play an important role in seed dispersal. Seeds are apparently carried great distances by rivers and may often be found in great abundance on ocean beaches. Central America and tropical South America; West Indies; West Africa. In Panama, known from tropical moist forest in the Canal Zone, Bocas del Toro, Panama, and Darién.