Stem twining, nodes swollen, whitish lenticels very common. Leaves 5-15 x 3-10 cm, ovate, base rounded to cordate, tip acute to acuminate, sparsely pubescent on the veins; petiole 1.2-5.5 cm long. Peduncle 2.5-6.0 cm long. Pedicels 1.2-3.8 cm long, puberulous. Bracts 7.5 mm long, lanceolate. Calyx divided nearly to the base, lobes 1.8-2.5 mm long, glabrous to pubescent. Corolla 6-6.5 mm long, cup-shaped, lobes c. 5 mm long, broadly ovate, obtuse. Follicles 7.5-10 x 1.7-3 cm, gradually tapering towards the blunt tip, longitudinally ribbed, minutely hairy. Seeds 1.2-1.3 cm long, broadly ovate, compressed margin broad, coma c. 3.7-4.4 cm long.