Extensive, perennial, twining shrub with long underground stolons; young shoots 4-angled; branches pendent; leaves large, opposite on swollen nodes, ovate-lanceolate or deltoid, acute-acuminate at apex, subcordate, 5-7 nerved at base, uppermost often passing into bracts; flowers large, in terminal, pendulous racemes, 20-30 cm long; bracts 2-3 cm large, obovate, foliaceous, upper small, persistent; bracteoles fulcate, elliptic, acute; calyx entire or crenulate in ring, teeth 5-9; corolla bluish purple, tube white, limbs subequally 5-lobed, deep blue, rarely white, stamens-4, attached at the throat of the tube, filament pubescent, widened below; ovary 2-locular; ovules 2 in each locule, style long, stigma very large, 2-lobed, flattened, fringed or folded along margin; capsule brown, about 2-5 cm long, glabrous or pubescent, globose or conical, 4 seeded; seeds ovoid, globose or subtrigonous, covered with soft, brown, scaly plates.