Aestivation: The Floral Arrangement MCQ - Practice Questions with Answers

Parts of a Flower - Aestivation

• The mode of arrangement of sepals or petals in floral bud with respect to other members of the same whorl is called aestivation.
• There are following types of aestivation in corolla and calyx:

1. Valvate Aestivation: When sepals and petals in a whorl just touch one another at the margin, without overlapping, as seen in Calotropis, it is called valvate aestivation.
2. Twisted Aestivation: If one margin of the appendage overlaps that of the next one and so on as seen in China Rose, Lady’s finger and cotton, it is called twisted.
3. Imbricate Aestivation: If the margins of sepals or petals overlap one another but not in any particular direction as in Cassia and gulmohar, the aestivation is called imbricate.
4. Vexillary Aestivation: In pea and bean flowers, there are five petals. The largest (standard) overlaps the two lateral petals (wings) which in turn overlap the smallest anterior petals (keel). This type of aestivation is called vexillary and the corolla is called papilionaceous.
5. Quincuncial Aestivation: When two petals are inner and two outer and one is partly inner and partly outer, it is called quincuncial. For example, Ranunculus.