Question

The standard petal of papilionaceous corolla is called ?

Answer 1

Hint: Aestivation is a term that is used for the mode of arrangement of sepals or petals with respect to the other members of the same whorl in the floral bud. Papilionaceous corolla can be described as basically the aestivation that can be seen in the family Papilionaceous. Here in the question they are asking about the name of the standard petal of papilionaceous corolla.

Complete answer:
Papilionaceous corolla, this type of aestivation includes the presence of five petals in it. Out of these petals, the largest one is called standard or vexillum, the two lateral petals are known as wings and out of them the smallest petals are termed as keels.
In this particular type of aestivation the standard or vexillum are arranged in such a way that it overlaps wings and wings are arranged in such a way that they overlap keels.
This type of aestivation can be seen in the Fabaceae family.

Therefore, we can conclude that the standard petal of papilionaceous corolla is called “Vexillum”.

Note:
There are mainly four types of aestivation and they are: Valvate aestivation in which the petals in a whorl just touch one another, hence they do not overlap each other. Then we have twisted aestivation in which one margin of appendage overlaps the margin of the other’s appendage. Then we have imbricate aestivation in which margins of petals overlap each other but not in a particular direction. And at last we have vexillary aestivation in which there are five petals, which we have read above in detail.