Corolla of a flower has morphologically three types of petals. Total number of petals are five. Out of these the anterior pair of petals are fused and the remaining three are free. The corolla shows the following type of aestivation.

Corolla of fabaceae members like pea has three types of petals out of which one is standard petal at the posterior side. Two lateral petals are called as wings or alae and the two anterior petals are fused and encircle the sex organs and completely inside. It shows vexillary aestivation.