The sweet potato (Ipomoea batatas) is a dicotyledonous plant that belongs to the family Convolvulaceae. It is an herbaceous perennial vine that has white and purple sympetalous flowers, large nutritious storage roots and alternate heart-shaped or palmately lobed leaves. Despite its popular name, the sweet potato is only very distantly related to the potato (Solanum tuberosum). It is a storage root, not a tuber or thickened stem like the potato, and belongs to the morning-glory family and not the nightshade family. Despite a physical similarity, yams are not related to the sweet potato either.
Ipomoea batatas is native to the tropical regions of the Americas. Of the approximately 50 genera and more than 1,000 species of Convolvulaceae, I. batatas is the only crop plant of major importance. Some others are used locally (e.g. I. aquatica (kangkong)), but many are poisonous. The genus Ipomoea also includes several garden flowers called morning glories. Some cultivars of Ipomoea batatas are also grown as ornamental plants