A large woody climber or twiner with quadrangular, strigose twigs. Leaves with 2-5 (-6) cm long scabrous petiole; lamina ovate or lanceolate-ovate, (6-) 8-15 (-16) x (3-) 4-12 cm, hairy on both sides except the scabrous costa and veins, ± cordate at 3-5-costate base, margins entire or coarsely toothed in the lower half, apically acute to acuminate. Flowers blue or violet with yellow centre, 6-8 cm long, c. 6 cm across, pedicellate, usually in axillary or terminal drooping racemes; bracts free or ± connate, ovate-oblong, 3-3.5 cm x 1.5-2 cm, acute-acuminate. Calyx truncate, velvety-rimmed, purplish. Corolla glabrous, tube 3-4.5 cm long, abruptly contracted near the base, lobes ± equal, patent, 3-4 cm long, obtuse. Stamens inserted at the throat, filaments flattened, anthers oblong, bithecous, anterior anthem with a single spur, posterior ones with 2, sharply curved spurs. Ovary glabrous. Capsule globular, contracted into a stout, c. 2 cm long flat beak.

Fl. Per.: June-August.

Type: Described from Bengal.

Distribution: India, China, Indo-China, Burma; introduced and naturalized in shiny tropical countries of Africa and New World.

Cultivated for its large showy flowers.