Sweet potatos are rich in dietary fiber, vitamin C and vitamin B6. In tropical areas they are a staple food crop. The tubers, leaves and shoots are all edible. The tubers are most frequently boiled, fried or baked. Tubers can also be processed to make starch and a partial flour substitute. The plants and tubers are frequently used for animal feed. Industrial uses include the production of starch and industrial alcohol.
The plant is a tropical annual vine that does not tolerate frost. Depending on the variety and conditions tubers mature in 3-9 months. Sweet potatoes rarely flower outside of the tropics and are primarily propagated by cuttings and tubers. Some variants are sold as house plants.
Sweet potatoes are belived to have originated in South America and spread throughout the tropical Americas into the Caribbean and across the South Pacific to Easter Island. Very likely the tuber drifted across the sea in a manner coconuts still do today.
Because the general Polynesian word for the sweet potato is kumara, and the South American word is kumar, it was originally thought that this was evidence of cross-Pacific contact between South America and Polynesia. However, linguists have determined that kumara and kumar are totally unrelated and have nothing to do with each other. So this cannot really be considered as evidence of pre-Magellan trans-Pacific crossings[?].
Farmers in the Southern United States started using the term "yam" to distinguish between the softer orange variety and the drier white varitey. The true yam is rarely found in the United States except as an import and the orange variety must be labeled "yam sweetpotato".