sweet potato, trailing perennial plant ( Ipomoea batatas ) of the family Convolvulaceae (morning glory family), native to the New World tropics. Cultivated from ancient times by the Aztecs for its edible tubers, it was introduced into Europe in the 16th cent. and later spread to Asia. It is now the most important of tropical root crops and is grown in many varieties (differentiated by their leaf shapes). In the United States it is cultivated chiefly in the South, though a few hardy varieties are grown as far north as Massachusetts. Sweet potatoes are used mostly for human consumption but are sometimes fed to swine. They yield starch, flour, glucose, and alcohol and are especially rich in vitamin A. The sweet potato is sometimes confused with the yam, which belongs to another family. Sweet potatoes are classified in the division Magnoliophyta, class Magnoliopsida, order Solanales, family Convolvulaceae.