whorl is known as aestivation.
Following are the is known as aestivation.
1) Valvate- when sepals or petals in a whorl just touch one another at the margin, without overlapping
Eg. Calotropis
2) Twisted - If one margin of the appendage overlaps that of the next one.
Eg- China rose, ladyfinger, cotton etc.
3) Imbricate - If the margins of sepals or petals overlap one another but not in any particular direction.
Ex- Cassia and gulmohar
4) Vexillary - In pea and bean flower, there are 5 petals, the largest (standard) overlaps the lateral petals (wings)
which in turn overlaps the two smallest interior petals (keel)