The arrangements of ovules within the ovary is known as placentation. What does the term placenta refer to? Name and draw various types of placentation’s in the flower as seen in T.S. or V.S.

Each ovary bears one or more ovules attached to a flattened, cushion-like structure called placenta.

The arrangement of ovules within the ovary is known as placentation. There are various types of placentations, namely:

a) Marginal - In 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. Example - pea.

b) Axile - 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.

c) Parletal - In parietal placentation, the ovules develop on the inner wall of the ovary or on peripheral part. Ovary is one-chambered but it becomes two-chambered due to the formation of the false septum, e.g., mustard and Argemone.

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

e) Basal - In basal placentation, the placenta develops at thebase of ovary and a single ovule is attached to it. Examples - sunflower, marigold.