Question

The flowers of many Angio spermic plants which show sepals and petals differ with respect to the arrangements of sepals and petals in respective holes’. Explain.

Answer 1

Hint: The plants which are capable of producing the flowers and bear their seeds in fruits are called angiosperms. They exist differently about 300,000 species. We can say that they are the largest and most assorted group within the Plantae kingdom. Thus, they are capable of representing 80 percent of all known living green plants approximately.

Complete answer: Aestivation is the name given to the mode of the prearrangement of sepals or petals in the bud of the flower, with respect to the affiliates of the same whorls. One can say that the valvate, imbricate, twisted and vexillary are the main types of aestivation.
Let us know more about these modes of aestivations:
Valvate: One can define the valvate aestivation as a type of aestivation in which the sepals or petals just touch one another at their margin, without imbrication
Twisted: One can define the twisted aestivations as a type of aestivation in which the one margin of sepals or petals intersects with that of next sepal or petal.
Imbricate: One can define imbricate aestivation as a type of aestivation in which the margins of the sepals or petals overlap one another but there is any particular direction.
Vexillary/papilionaceous: One can define Vexillary or papilionaceous aestivation as a type of aestivation in which the largest petal (which is called as the standard petal) among the five petals overlaps the two lateral petals (which is called as wings) which in turn overlap two smallest anterior petals (which is called as Keel petals).

Note:
The Vexillary or papilionaceous aestivation is seen in the pea and bean flowers. It is said that the flowers in the plants such as the gulmohur, Casia consist of this type of aestivation. It is said that the flowers in the plants such as the China rose, ladies’ finger, cotton consist of this type of aestivation. It is said that the flowers such as the Calotropis consist of this type of aestivation.