Distribution     
Probably originated in continental Asia. Cultivated throughout tropical Asia, also in South America, Africa, Australia, and the Southeast US, sometimes naturalizing. In the Marquesas cultivated or formerly cultivated and sometimes persisting.

Habit
Plant glabrous; stems unarmed though rather rarely rough or warted close to the soil, climbing to 10 m, quadrangular and as a rule conspicuously 4-winged above the very base at which the leaves are not decussate; bulbils abundant, more so in some races than in others. Tuber deeply buried in soil, cylindrical, clavate, globose or pyriform, variously lobed, fingered or fascinate, flesh white or ivory colored or purple, either superficially or throughout.

Leaves
Leaves generally a few alternate at the very base, thereafter opposed, herbaceous, subsagittately or subhastately ovate, rarely subhastately deltoid, shortly acuminate, usually to 22 cm long, 15 cm wide, upper surface bright green, 5-nerved; petiole about as long as the lamina, sometimes marginally frilled, sometimes with the pulvini suffused with purple.   

Flowers
Male flowering axes 1-2 together, aggregated on leafless branches which only rarely exceed 30 cm long, with up to 20 flowers spaced about their own diameter apart; buds somewhat flattened at the base, otherwise nearly globose 1 mm long, at times the axis a little zigzag with the buds on the angles. Female flowering axes 1 from an axil, decurved but rigid, to 60 cm long with about 20 flowers, angled or at the base narrowly winged.   

Fruit
Capsules at the apex slightly retuse, at the base obtuse; wings 17-20 mm long, 15 mm wide; stipe 3-4 mm long.