Peanuts, popularly known as groundnuts, monkey nuts, pig nuts, etc belong to the fabaceae (bean) family. Peanuts, arachis hypogaea is a legume species, and native to south america, mexico and central america. An annual herbaceous plant, that grows almost to ground level, with very slender stems, leaves that are opposite and pinnate with four leaflets, flowers that are pea-shaped, and fruits (legumes) that are basically seeds that sprout and mature underground.