Write the types of Aestivation and Explain .

Explanation

Aestivation: Arrangement of sepals and petals in the flower bud.
1. Valvate: Margins of sepals or petals do not overlap but just touch each other. Eg: Calyx in members of Malvaceae, Calotropis, Annona.
2. Twisted or Convolute or Contorted: One margin of each petal or sepal overlapping on the other petal. Eg: Petals of chinarose.
3. Imbricate: Sepals and petals irregularly overlap on each other, one member of the whrol is exterior, one interior and rest of the three having one margin exterior and the other interior. Eg: Cassia, Delonix. There are 3 types. 1. Ascendingly imbricate 2. Quincuncial 3. Vexillary.
4. Quincuncial: It is a type of imbricate aestivation in which two petals are external and two internal and one petal with one margin internal and the other margin external. Eg: Guava, calyx of Ipomoea, Catharanthus.
Vexillary: Large posterior petals both margins overlap lateral petals. Lateral petals other margin overlaps anterior petals. Eg: Pea, bean.