Despite the similarity of their names, the potato and the sweet potato are not at all related. Early in Christopher Columbus' explorations of the islands of the Caribbean, he dined on several different varieties of sweet potato. Sweet potatoes thrived in the area's warm, tropical climate and were a common food in the regional diet.

Native to Peru, as is the white potato, the sweet potato rapidly traveled to other parts of South America as well as to Mexico, and possibly was taken by sea to the islands of the mid-Pacific and on to New Zealand, long before Columbus. A staple in the island nation of Papua New Guinea, the sweet potato is also important in several Asian countries, particularly as a fall-back food if the rice crop fails. China grows most of the world's crop. Sweet potatoes in many guises are popular in Japan where specialized restaurants serve all-sweet-potato items.

A U.S. southern standby, the sweet potato was another crop nurtured by African slaves. The sweet potato improved soils depleted by the growing of cotton.

No, the sweet potato is not a yam and a yam is not a sweet potato. A yam is a tropical plant not grown in the continental United States, and not generally found even in Hawaii.