Liana; trunk to 3 cm diam; bark smooth, greenish; stems with 4 phloem arms in cross section; twigs subterete to tetragonal, +/- glabrous, drying tan to greenish, the nodes lacking glandular fields; tendrils simple; pseudostipules small, 4-scaled, usually narrow. Leaves 2- or 3-foliolate; petioles 1-6.5 cm long, puberulent; petiolules 0.5-4 cm long; leaflets narrowly ovate, acute to acuminate, rounded to shortly subcordate at base, 5-17 cm long, 2-7.5 cm wide, glabrous to puberulent along main veins; reticulate veins prominulous. Racemes terminal or axillary; flowers with a faint musky odor (fide Gentry), each subtended by a deciduous bract; rachises, pedicels, and calyces puberulent; calyx cupular, 5-15 mm long, 5-toothed but +/- bilabiate, usually with submarginal, sunken glands; corolla bright yellow, 4-8 cm long, puberulent outside and on lobes inside, the tube slender, the apical part campanulate, the 2 upper lobes erect, extending horizontally in front of the tube, the other 3 variously reflexed; stamens slightly exserted, the pairs nearly equal, the longer 3.5-3.9 cm long; staminodium 12-21 mm long; pistil 5-6 cm long; ovary narrowly cylindrical, 4-5 mm long, 1.5-2 mm wide, puberulent. Capsules unknown (those of the genus oblong-linear, thick, flattened, woody). Standley 40912 (US).