Geocarpy

Geocarpy 

a method plants have of distributing fruit by injecting the ovary into the soil. Geocarpy is characteristic, for example, of peanuts and one species of clover. The fruit usually enters the soil as a result of the unique and complicated flexure of the fruit stalk. In the peanut a special organ—the gynophore—forms under the ovary and grows until the ovary enters the earth up to a depth of 10 cm. Then the gynophore’s growth ceases, and the ovary begins to grow, turning into a fruit. Some geocarpic plants, for example, the South American bitter cress, also have aerial fruits along with underground ones. Geocarpy is sometimes associated with cleistogamy.