The arrangement of ovules within the ovary is known as placentation. What does the term placenta refer to? Describe the various types of placentation found in flowers.

(N/A) $\Rightarrow$ The placenta is a soft,cushion-like tissue within the ovary to which the ovules are attached.
$\Rightarrow$ The arrangement of ovules within the ovary is known as placentation. The major types of placentation are marginal,axile,parietal,free central,and basal.
$\Rightarrow$ Marginal Placentation: In this type,the placenta forms a ridge along the ventral suture of the ovary,and the ovules are borne on this ridge in two rows,as seen in pea.
$\Rightarrow$ Axile Placentation: In this type,the placenta is axial and the ovules are attached to it in a multilocular ovary,as seen in China rose,tomato,and lemon.
$\Rightarrow$ Parietal Placentation: In this type,the ovules develop on the inner wall of the ovary or on the peripheral part. The ovary is one-chambered but may become two-chambered due to the formation of a false septum,as seen in mustard and Argemone.
$\Rightarrow$ Free Central Placentation: In this type,the ovules are borne on a central axis,and septa are absent,making the ovary one-chambered,as seen in Dianthus and Primula.
$\Rightarrow$ Basal Placentation: In this type,the placenta develops at the base of the ovary,and a single ovule is attached to it,as seen in sunflower and marigold.