The peanut is a species in the familyFabaceae.The peanut was probably first domesticated and cultivated in the valleys of Paraguay. It is an annualherbaceous plant growing 30 to 50 cm tall. The leaves are nyctinastic, opposite, pinnate with four leaflets each leaflet is 1 to 7 cm long and 1 to 3 cm across.The flowers are a typical peaflower in shape, 2 to 4 cm across, yellow with reddish veining. The specific name, hypogaea means "under the earth" after pollination, the flower stalk elongates, causing it to bend until the ovary touches the ground. Continued stalk growth then pushes the ovary underground where the mature fruit develops into a legume pod, the peanut – a classical example ofgeocarpy. Pods are 3 to 7 cm long, normally containing 1 to 4 seeds.