Peanut — The peanut, or Groundnut (Arachis hypogaea), is a species in the legume family Fabaceae native to South America, Mexico and Central America. It is an annual herbaceous plant growing to 30 to 50 cm (1 to 1½ ft) tall. The leaves are opposite, pinnate with four leaflets (two opposite pairs; no terminal leaflet), each leaflet 1 to 7 cm (⅜ to 2¾ in) long and 1 to 3 cm (⅜ to 1 inch) broad. The flowers are a typical peaflower in shape, 2 to 4 cm (¾ to 1½ in) across, yellow with reddish veining. After pollination, the fruit develops into a legume 3 to 7 cm (1 to 2 in) long containing 1 to 4 seeds, which forces its way underground to mature.
The plant’s name combines the morphemes pea and nut, causing some confusion as to the nature of the fruit. Although a nut in the culinary sense, in the botanical sense the fruit of the peanut plant is a woody, indehiscent legume and not a nut. The word pea describes the edible seeds of many other legumes in the Fabaceae family, and in that sense, a peanut is a kind of pea.
Peanuts are also known as earthnuts, goobers, goober peas, pindas, jack nuts, pinders, manila nuts and monkey balls. (The last of these is often used to mean the entire pod, not just the seeds. In the UK these are sold as monkey nuts.)
Harvesting peanuts occurs in two stages. First a machine is used to cut off the main root of the peanut plant by cutting through the soil just below the level of the peanut pods. Then the same machine lifts the “bush” from the ground and shakes it. Then the machine inverts the bush to leave the plant upside down on the ground to keep the peanuts out of the dirt. This allows the peanuts to slowly dry to a bit less than a third of their original moisture level over a period of 2-3 weeks while they are left upside down on the field.
Edible peanuts account for two-thirds of the total peanut use in the United States. Popular confections include salted peanuts, peanut butter (sandwiches, candy bars, and cups), peanut brittle, and shelled nuts (plain/roasted). Salted peanuts are usually roasted in oil and packed in retail size, plastic bags or hermetically sealed cans. Dry roasted, salted peanuts are also marketed in significant quantities. The primary use of peanut butter is in the home, but large quantities are also used in the commercial manufacture of sandwiches, candy, and bakery products. Boiled peanuts are a preparation of raw, unshelled green peanuts boiled in brine and typically eaten as a snack in the southern United States where most peanuts are grown.