Plants annual. Stem and branches slender, sulcate-angular. Tendrils filiform, glabrous. Petiole slender, 6-9 cm, subglabrous; leaf blade broadly ovate-cordate, 8-10 × 6-8 cm, membranous, both surfaces puberulent, palmately 7-veined, margin irregularly dentate, apex caudate-acuminate; sinus subquadrate, 1-1.5 cm deep, 1.5-2 cm wide. Plants dioecious. Male flowers in a raceme; peduncle slender, 6-8 cm; pedicels filiform, 2-5 cm; calyx segments lanceolate-subulate, ca. 3 mm; corolla pale yellow, rotate, glandular hairy at base; segments broadly lanceolate, ca. 9 mm, 1-veined, apex acuminate; filaments free, ca. 0.8 mm, glabrous; anthers connate at base, elliptic; cells erect, puberulent; rudimentary ovary absent. Fl. Jul-Sep.