Slender, scandent, dioecious, less frequently monoecious, annual herb; leaves usually 5, sometimes 3-7 lobed, cordate, reniform, not acuminate, entire, denticulate, pubescent or puberulent on both surfaces; tendrils 2-3 fid; flowers dioecious, large about 4-5 cm across; bracts oblong, entire, large, sheathing; male flowers on long pedunculate racemes, 8-15 flowered, pedicels long; calyx tube long, subcylindric, mouth shortly campanulate, teeth-5, short; petals-5, connate at the base, very long, fimbriate; stamens-3, anthers almost included, connate, linear, one 1-celled, two 2-celled, cells conduplicate, filaments very short ovoid; female flowers solitary on long peduncles, calyx and corolla as in male flowers; ovary globose, 1-celled, style long, stigmas-3, oblong, bifid, exserted, placentas-3, parietal, ovules numerous; fruits elongate-cylindric, sometimes contorted, smooth, often with white strips along the length; seeds ovate-oblong, corrugate.