The mode of arrangements of sepals or pe | Class 11 Biology Chapter Morphology of Flowering Plants, Morphology of Flowering Plants NCERT Solutions

There are different types of aestivation of calyx and corolla:

In calyx: Mode of arrangements of sepals in the bud is known as aestivation.

1. Valvate: In the case sepals or petals in a whorl just touch one another at the margin without overlapping or turning.

1. Induplicate: Margins projecting inward.
2. Reduplicate: Margins projecting outward.
3. Involute: Margins rolled inward.

1. Twisted: In this case, margin of sepals are overlapping regularly i.e., one margin of a sepal overlaps the next and the other margin is overlapped by a preceeding sepal.
2. Imbricate: In this case, the margins of sepals overlap each other in such a way that one is internal, one is external and the others are partly internal and partly external.
3. Quincucial: Out of five sepals two are anterior, two are exterior and the fifth one has one margin exterior and the interior.  

In corolla: Mode of arrangements of petals in relation to one another in the flower bud is known as aestivation.

1. Open: Petals of a whorl are sufficiently apart from each other.
2. Valvate: Petals of a whorl meet by their edges but do not overlap.

1. Induplicate: Margins projecting inward.
2. Reduplicate: Margins projecting outward.
3. Involute: Margins rolled inward.

1. Twisted: In this case, margin of petals are overlapping regularly i.e., one margin of a petal overlaps the next and the other margin is overlapped by a preceeding sepal.
2. Imbricate: Margins of petals overlap irregularly. Out of five petals, one is completely internal, one is completely external and in each of the remaining three petals one margin is internal and the other is external. 
3. Quincucial: It is a modification of imbricate aestivation in which two petals are internal, two are external and the fifth one has one margin external and the other margin internal.