Yam is the common name for some plant species in the genus Dioscorea (family Dioscoreaceae) that form edible tubers. These are perennial herbaceous vines cultivated for the consumption of their starchy tubers in Africa, Asia, Latin America, the Caribbean and Oceania. There are many cultivars of yam.
Although some varieties of sweet potato (Ipomoea batatas) are also called yam in parts of the United States and Canada, sweet potato is not part of the family Dioscoreaceae but belongs in the unrelated morning glory family Convolvulaceae. If you are unsure as to whether you are eating yams or sweet potatoes use the key in the last illustration to determine what you have!
This post is part of the Wordless Wednesday meme,
and also part of the ABC Wednesday meme,
and also part of the Food Friday meme.