The corolla is the second whorl of the flowering plant.
It is basically the petals that are present in the flower that can be of different shapes, sizes, and colours.
Papilionaceous corolla is a special type of aestivation found in the corolla in the family of Papilionaceae.
There are five petals in this aestivation in which the largest petal is known as the standard or vexillum which is seen to overlap the two lateral petals; these two lateral petals overlap the smallest two anterior which are also called keels.
