Herbs twining, with glabrous or hirsute axial parts. Stems glabrous or nodes hirsute. Petiole 1-5 cm, sometimes minutely tuberculate; leaf blade cordate-sagittate to narrowly hastate, 5-12 X 1-6 cm, glabrous, apex acuminate, mucronulate; lateral veins 5 or 6 pairs. Inflorescences axillary, 1- to few flowered; peduncle 5(-9) cm or shorter; bracts 2, ± ovate, 0.5-1.5 cm, glabrous. Pedicel angular, 1.3-3.5 cm. Sepals unequal; outer 3 larger, attenuate-ovate to lanceolate, 1.5-2.2 cm, margin incurved, apex mucronate, strongly 3-keeled abaxially, keels toothed basally, glabrous. Corolla purplish to red, with a darker center, narrowly funnelform, 2.5-4 cm, glabrous. Stamens included; filaments pilose below middle. Ovary conical, glabrous. Style filiform, ca. 5 mm; stigma capitate, 2-lobed. Capsule pale brown outside, whitish inside, ovoid to globose, 1-1.5 cm. Seeds black-brown, ovoid, ca. 5 mm, densely tomentellous.