Yams are a group of monocot plants, precisely speaking, a group of perennial herbaceous vines grown for their starch-rich, edible tubers. They belong to the family Dioscoreaceae and genus Dioscorea. Yams are widely grown in both temperate and tropical parts of the world and considered as an important food crop in the tropical areas of America, Asia and Africa. Yams are a rich source of carbohydrates. There are white yams, purple yams and yellow yams, depending on the colour of the tuber flesh.