Dioscroaceae, Dioscorea bulbifera, potato yam, air potato, oruka, oroko (Luo), mutokera (Giriama), mutokera (Luhya)
The mere concept of this plant seems to be unsettling to some people because it’s like a potato but it grows on a vine, above ground, and that defies convention.
The air potato can be roasted or boiled like sweet potato, they are often soaked in cold water for two days, to disolve poisoinous compunds before consumption. The plant does have underground tubers although they are not eaten to my knowledge. The underground tubers are, however, used for medicinal purposes, peeled and given to children to treat measles.
This species is very rare in the wild, possibly entirely absent. Cultivation of the crop has declined considerably in recent years.
Var. bulbifera is the wild variety and is said to be poisonous. Var. anthropophagorum is a cultivated variety, which has reduced or absent underground tubers, and larger, angular areial tubers.
var. Sativa is an Indian variety with edible roots.