Annual, large or small, extensively hairy, climber; stem long, 5-angled or grooved, little villous; tendrils 2-3 fid; leaves reniform or orbicular, 5-angled or lobed, denticulate, scabrous, punctuate on both surfaces, pubescent on nerves beneath; petiole about 5 cm long; flowers monoecious, bracteate, large, bright yellow, male flowers racemed on long peduncles, clustered in axils; in male flowers: peduncles about 10-12 cm long; calyx tube short, broadly campanulate; petals-5, yellow with elevated, hairy, green veins, obovate, scabrous, spreading; stamens 3 rarely 5, 1-celled others 2-celled, sometimes all, unilocular, filaments shortly villous at base; female flowers solitary on 3-8 cm long peduncle often in same axil; calyx and corolla same as in males; ovary oblong, style cylindric, stigma 3-lobed, ovules many, horizontal; fruit large, cylindric, usually smooth, fibrous; seeds many oblong, compressed.