Aestivation is the arrangement inside a bud of the floral parts until it blooms into a flower. Sepals or petals’ arrangement in a floral bud concerning other members of the same whorl is called as
aestivation. Different types of aestivation are:
- Twisted – if one margin of the appendage overlaps the adjacent one, it is twisted, which can either be
clockwise or anti-clockwise. Example – cotton
- Valvate – In a whorl when petals or sepals just touch each other at the margin without overlapping, it is
valvate. Example – Calotropis
- Imbricate – It is imbricate when petals or sepals overlap each other but not in any definite direction as
observed in Gulmohar
- Vexillary – The largest petal overlaps the two lateral petals which in turn overlap the two smallest
anterior peel is vexillary aestivation. Example – Bean flower
Vexillary aestivation is the unique arrangement where the other smaller petals are covered by one large petal. The larger petal is called a vexillum, while the two curved petals which are laterally positioned are called wings. In this destination, the two inmost, boat-shaped petals are called keels.
Examples: Polypetalous, papilionaceous.