Annual herb; stems long-running or trailing, scabrid, bearing branched tendrils, finely puberulent with more scattered long hairs. Petioles long, hollow, with indumentum as on stems. Lamina very variable in size and shape, usually variously lobed and triangular or broad-ovate, to c. 40 × 30 cm, more rarely not lobed and merely angular or undulate, ± hispid or scabrid; margin denticulate; base broad-cuneate, situated in a deep obtuse sinus. ♂ fls: peduncles to c. 30 cm long, ± hispid or scabrid; calyx 1.5-3.5 cm long, hairy, lobed to c. 1/2 way; lobes linear to subulate. Corolla 5-8 cm long, with prominent veins, hairy on both sides; lobes ovate, ± apiculate. ♀ fls: peduncle short, stout, becoming hard, corky, angular and sometimes expanded at apex at fruiting; calyx and corolla similar to ♂ but often larger. Fr. extremely variable, developing a fairly to very hard rind, smooth or knobbly, large (to > 50 cm long in cultivation), commonly cylindric to oblong and green or greenish white, occasionally globose or subglobose and orange, white, or greenish; pulp white or pale green; margin sometimes scalloped. Seed whitish, ellipsoid; margin raised, obtuse.