Tropical Zone Gardening: Plant ID please, 2 by EnfoGreg

EnfoGreg wrote:
Hello,

we live in the central part of Peru with tropical, or sub-tropical climate (high jungle). Recently we've encountered a strange, stone-looking fruit, growing on a vine, locally known as "papa del aire" (potato of the air) or "papa del monte" (potato of the jungle). The taste resembles much that of the potato, and - just like the potato - it can be cooked or fried. Does anyone know this plant?