Describe the various types of placentations found in flowering plants.

(N/A) Placentation refers to the arrangement of ovules within the ovary. It is of five basic types:
$(A)$ Marginal placentation:
The placenta forms a ridge along the ventral suture of the ovary,and the ovules are borne on this ridge,forming two rows. This is found in peas.
$(B)$ Parietal placentation:
When the ovules develop on the inner wall of the ovary or on the peripheral part,it is called parietal placentation.
$(C)$ Axile placentation:
In axile placentation,the placenta is axial and the ovules are attached to it in a multilocular ovary. Examples include China rose,tomato,and lemon.
$(D)$ Basal placentation:
The placenta develops at the base of the ovary,and a single ovule is attached to it. It is found in sunflower and marigold.
$(E)$ Free central placentation:
In free central placentation,the ovules are borne on the central axis,and septa are absent. This is found in Dianthus and primrose.