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The arrangement of accessory whorls (calyx, corolla) in relation to one another in the floral bud is called as aestivation.

The different types of aestivation are:




1. Valvate

Petals or sepals meet each other at the edges.

Arranged without overlapping

Calyx of Hibiscus

2. Twisted

Petals or sepals show overlapping.

Overlapping is done by one margin of each petal over the margin of adjacent petals

Corolla of Hibiscus

3. Imbricate

Margins of petals overlap each other in such a way that one petal is completely external, one petal is completely internal

Cassia, Bauhina

4. Vexillary

It is seen in papilionaceous form of corolla.

Posterior petal is external and largest, it almost covers the two lateral petals and lateral petals in turn overlap two smallest anterior petals

Pisum sativum (Garden Pea)

5. Quincuncial

Margins of petals overlap each other in such a way that two petals are completely external, two petals are completely internal

Psidium guajava


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