Yam

Yam is the common name for edible-tubered species in the genus Dioscorea, a starchy staple across tropical and temperate regions with over 95 percent of world production concentrated in Africa. Unlike most staple crops, yam was not domesticated once: three separate species were brought into cultivation independently on three different continents, white yam (Dioscorea rotundata) in Africa, water yam (Dioscorea alata) in Asia, and cush-cush yam (Dioscorea trifida) in South America, each its own domestication event rather than one crop spreading from a single origin. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/