The groundnut is commonly referred to as the peanut, but scientifically this plant has the name Arachis hypogaea. Originating in South America, the groundnut is familiar in many areas of the world as a nut and for its oil extract. Technically, the groundnut is not a real nut, but rather is part of the legume family; this includes such foods as peas and beans.
Spanish explorers were the first to spread the groundnut plant throughout the Americas from its localized origin in the region of present-day Bolivia and Argentina. According to the Consultative Group on International Agriculture Research (CGIAR), the groundnut is primarily grown in developing countries such as India, Nigeria and Indonesia, but the USA and China also produce commercial groundnut crops. The majority of the nuts are processed into oil, says the CGIAR, as each peanut is made up of about 50 percent oil.
Each plant produces pods, which protect the peanuts inside. These pods originate as fertilized flower ovaries, which then push into the ground and develop into pods, with three to five seeds inside. Each seed is generally called a peanut by the people who eat them, either by popping the pod open to eat the seed as a snack, or by eating the peanuts after they have been processed to remove the shell. Examples of groundnut seeds that are widely available in shops include salted or roasted.
Characteristics of the plant itself include a root system that is buried deeply in the ground relative to its maximum potential height of about 24 inches (60 cm.) As the plant is an annual, it grows in one year, dies, and is replaced by its seeds. The stem is covered in hairs and has branches that spread out or stand up in the air. Peanut flowers are yellow, and the plant grows best in loamy soil. Due to its preference for warm climates, the groundnut only grows in countries that are within a band of about 40° either side of the Equator.
As well as being 50 percent oil, the nut is high in protein, at about 25 percent, with 20 percent carbohydrate. This makes the peanut a useful source of nutrition, as it is high in calories. In addition, peanuts contain vitamin E, vitamin K and B-vitamins, along with niacin. Animals can also benefit from peanut harvests, as after the oil is extracted, a dry cake is left over which can form a nutritious addition to feed.