In a pea flower, five petals are arranged in a specialized manner with one posterior, two lateral and two anterior. These are named as _______, _______ and ________ respectively.

Pea belongs to Fabaceae family. In a pea fl ower, fi ve petals are arranged in a specialized manner with one posterior, two lateral and two anterior. These are named as standard/vexillum, wings/alae and keel/carina respectively. This is Vexillary aestivation. It facilitates Piston mechanism of pollination. The posterior/standard petal is the largest and most upright petal. It is the landing platform for the insect. Standard is flanked on either side by two lateral petals known as “wings”. The wing petals in turn overlap the two anterior petals, known as keel petals. The keel petals are partially fused to form a boat shaped structure. They enclose the
male and female reproductive structures of the flower.