What is the Difference Between Marginal and Parietal Placentation?

The key difference between marginal and parietal placentation lies in the location of ovules within the ovary of flowering plants. Here are the main differences between the two types of placentation:

• Marginal Placentation:
• Ovules are attached to a ridge made from the placenta at one of the margins of the ovary.
• There is a single placenta that develops along the junction of the two fused margins.
• This type of placentation is a characteristic property of the family Fabaceae.
• Examples of plants with marginal placentation include peas.
• Parietal Placentation:
• Ovules are attached to the periphery or inner wall of the ovary.
• The ovary is unilocular and has two or more longitudinal placenta.
• This type of placentation is a characteristic property of Brassicaceae or Cruciferae.
• Examples of plants with parietal placentation include Argemone.

In summary, marginal placentation is characterized by ovules attached to a ridge at the margin of the ovary, while parietal placentation is characterized by ovules attached to the periphery or inner wall of the ovary.

Comparative Table: Marginal vs Parietal Placentation

Here is a table comparing marginal and parietal placentation:

Marginal placentation is characterized by a single placenta that develops along the junction of the two fused margins in the ovary, while parietal placentation has two or more placenta present in the ovary, with ovules attached to the inner or outer wall. Both types of placentation are found in unilocular ovaries and are characteristic properties of certain plant families.