Standl., J. Wash. Acad. Sci. 15:459.1925
Liana, essentially glabrous; sap milky; younger stems often with corky lenticels; older stems becoming totally covered with corky tubercles. Leaves opposite; petioles 1-3 cm long, swollen, with several sharp glands in axils; blades mostly obovate, acute to rounded and cuspidate at apex, rounded to obtuse at base, 14-28 cm long, 9-18.5 cm wide, coriaceous, glabrous to minutely puberulent; elsewhere venation sometimes prominent below, with
a submarginal collecting vein. Corymbs axillary, longpedunculate; peduncles and pedicels densely puberulent to glabrous; pedicels to 4 cm long; flowers 5-parted; calyx lobes triangular, 10-15 (20) mm long, pubescent at least near base, with a single squamella inside each lobe; corolla salverform, yellow, 2.5-3.5 cm long, puberulent outside, with 5 white epistaminal appendages held above the prominently raised rim, the rim white to pink, the tube ca 2 cm long, pubescent near anthers; stamens included (just below rim); anthers ca 4 mm long, connate and glued to stigma; stigma 1; nectaries thick and fleshy, shorter than ovary. Follicles paired, 25-35 cm long, often covered with corky tubercles like those of stem; seeds ca 2 mm long, with tufted trichomes at apex, the trichomes 3.5-4 cm long. Aviles 38.
Rare, in the forest. Flowers during the dry season and in the early rainy season (January to September, especially in July). The fruits mature in the late rainy to early dry seasons (October to January), especially in the dry season.
Known only from Panama, from tropical moist forest in the Canal Zone, Chiriqui, and Darien, from premontane wet forest in Colón and Panamd, and from tropical wet forest in Panama and Darien.