Gynoecium:

1. The gynoecium or pisit is the fourth essential whorl of female reproductive part of the flower  and may be composed of one or more carpel.
2. A carpel has three distinct parts, namely the ovary, style and stigma and is a highly modified leaf folded along the midrib.
3. A cushion like parenchymatous outgrowth develops on the ventral suture called placenta on which the ovules are borne.
4. The ovary is basal swollen portion of the pistil containing one of more  chambers or loculi and accordingly  the ovary is known a unilocular, bilocular, trilocular, tetralocular, pentalocular and multilocular.
5. The wall of the ovary after fertilization is known as pericarp.
6. After fertilization, at maturity, the ovary develops into a fruit while ovules form seeds.

 

Forms of gynoecium

On the basis of number of carpels is the gynoecium is of following types:

1. When gynoecium is represented by a single carpet it is termed as monocarpellary e.g. Pea.
2. The ovary is described as simple ovary. If the number of carpels in the gynoecium is 2, 3, 4 and 5. It is said to be bicarpellary, tricarpellary and pentacarpellary respectively.
3. When the gynoecium contains more than five carpels, it  is  called polycarpellary.

On the basis of free and fused carpels the gynoecium is of following nature:

Apocarpous: There are two or more carpels in  a gynoecium which are free from each other e.g. Ranunculus (Buttercup), Aconitum.

Syncarpous: In this form two or more carpels are fused together to form a single compound ovary e.g. Petunia, Althaea etc.