Basal placentation: The placenta is at the base (bottom) of the ovary and a single ovule is attached to it.
Example: Sunflower, marigold.
Parietal placentation: Here ovary is one-chambered but it becomes two- chambered due to the formation of the false septum. The ovules develop on the inner wall of the ovary or on peripheral part.
E.g. - mustard and Argemone.
