WHITE AIAME Herbaceous plant frequently grown in tropical countries. Yams are starched tubers of African origin, which botanically belong to the genus Dioscorea. The white yam is the Dioscorea rotundata, while the yellow yam is the cayenensis dioscorea. The word yam comes from the African word "nyami", meaning "to eat". Although yam is now consumed almost all over the world, the origin of its cultivation has been found in Africa and Asia since prehistoric times. Today it is a staple in South America, Africa, the Antilles and the Pacific Islands.