Perennial climbers, the stem narrowly 3-5-winged, sulcate or angular, glabrous or sparsely pilose. Leaves variable, orbicular, broadly ovate, ovate-lanceolate or lanceolate, 5-15 cm long, basally cordate to hastate, apically acuminate, acute or obtuse to rounded, the margins entire or more commonly dentate to shallowly lobed, the upper surface glabrous or nearly so, the lower surface pubescent. Flowers solitary or cymose. Sepals ovate or broadly ovate, the outer 1.5-2.5 cm long, the inner 2 cm long, acute or shortly acuminate, the outer pubescent, the inner glabrous. Corolla white or white with a yellowish base, campanulate to broadly funnel-shaped, 3-4.5 cm long. Fruits capsular, depressed-globose, 1.5 cm wide. Seeds dull black, glabrous.