Peanut

This popular nut is not a nut, but the seed of a small leguminous bush, Arachis hypogaea, which pushes its thin, woody fruit capsules below ground as they mature. The peanut was domesticated in South America, probably Brazil, around 2000 BCE, and was an important crop in Peru before the time of the Incas. In the 16th century, the Portuguese took it to Africa, India, and Asia, and it soon became a major source of cooking oil in China (peanuts have double the oil content of soybeans). It wasn’t until the 19th century that Americans thought of peanuts as anything but animal feed, and not until the early 20th century that the remarkable agricultural scientist George Washington Carver encouraged southern farmers to replace weevil-ravaged cotton with peanuts.