In the diagram of types of placentation given below A, B, C and D respectively represent
Axile, basal, parietal and free-central
An example of axile placentation is lemon (Citrus sp.). In this placentation, the ovules are borne on the inner wall of the ovary. Basal placentation has a single placenta at the base and a single ovary. In parietal placentation, two or more placentae develop along the wall of the ovary. In free central, the ovules are not connected with the ovary wall by any septum.