Placentation

Placentation- attachment of ovules to the ovary wall is called as Placentation.

The types are: 1. Marginal 2. Parietal 3. Axile 4. Free-central 5. Superficial or Laminar 6. Basal.

1. Marginal Placentation:

The ovules in rows near the margin on the placenta fromed along the ventral suture. It occurs monocarpellary and ovary is unilocular. E.g. Legumes

2. Parietal Placentation:

The placenta is formed by the swelling up of cohering margins and on the latter develop the ovules in rows. It occurs in bicarpellary or multicarpellary but unilocular ovary. E.g. Papavaraceae

3. Axile- The placantae develop from the central axis which correspond to the confluent margins of carpels. It occurs in bi-to multilocular ovary. E.g. Solanaceae, Malvaceae

4. Free Central- The placenta develop in the ovary as a porlolongation of floral axis and the ovules are attached on this axis. It occurs in multicarpellary but unilocular ovary. E.g. Primulaceae

5. Laminar or Superficial- The ovules develop over the inner surface of the carpels. It occurs in multicarpellary ovary. E.g. Nymphaea

6. Basal- The placenta develops directly on the thalamus and bears a single ovule at the base of the unilocular ovary. E.g. Asteraceae