Two different edible tubers, the sweet potato and yam, are widely raised and consumed in the South, their outward similarity leading to a confusion in names. The sweet potato is a native of the Western Hemisphere, scientifically known as Ipomoea batatus. Its relatives include the morning glory; native Americans consumed its taproot, occasionally finding thirty-pound specimens. The yam family is particularly Widespread in the tropics; many species are still consumed in the very southern states, even more in the Caribbean. The prized species, Discorea alata, was brought from Africa. The etymology of yam is, in fact, a mirror of the slave trade: it comes from the Portuguese inhame, derived from the Senegalese nyami—to eat. The sweet potato is by far the more common of the two. Water content and nutritional value differ, but in cooking and in speech the two are practically interchangeable.