How can you differentiate between free central and axile placentation?

The arrangement of ovules within the ovary is known as placentation.

When the placenta is axial and the ovules are attached to it in a multilocular ovary, the placentaion is said to be axile. Examples - china rose, tomato and lemon.

When the ovules are borne on central axis and septa are absent, the placentation is called free central. Examples - Dianthus and Primrose.