Placentation refers to the arrangement of:

Ovules within the ovary

Placentation refers to the arrangement of ovules within the ovary of a flower. The ovary is the basal bulged part of the pistil, which is the female reproductive structure of the flower. It contains one or more ovules, which are structures that develop into seeds after fertilization.

The placenta, located inside the ovarian cavity (locule), is the specific region within the ovary where the ovules are attached. The placentation describes how these ovules are arranged and attached to the placenta. It varies among different plant species and can have various patterns or types.

Different types of placentation include:

Marginal Placentation, Axile Placentation, Parietal Placentation, Free Central Placentation, and Basal Placentation.

These different types of placentation have implications for the arrangement and development of seeds within the ovary after fertilization. They can affect the number, position, and orientation of the seeds within the fruit that forms from the mature ovary.

In summary, placentation refers to the arrangement of ovules within the ovary of a flower, determining how the seeds will be positioned and distributed within the fruit.