winged bean Psophocarpus tetragonolobus, a tropical, climbing, leguminous plant, whose pods have four wavy ridges running along them from end to end. It is also known as Manila or Goa bean, and sometimes as princess or asparagus pea (a name also applied to the winged pea). The pods may be 30 cm (1') long.
The plant is probably native to SE Asia. Indonesia and Papua New Guinea are centres of genetic diversity. Distribution now extends to W. Africa, the W. Indies, and other tropical areas; and much interest is being shown in the possibility that the plant, a good source of protein, could make a major contribution to world food supplies. A remarkable feature of the plant is that all parts are edible: shoots, leaves, flowers, pods, seeds, and (although sometimes too small for use) tubers. The tubers of leguminous plants, such as this one, provide much better nutrition than other root crops. Whereas the latter are low in protein, tubers of leguminous plants benefit from nitrogen fixation and are consequently rich in protein.