Question

When the margins of sepals or petals overlap one another without any particular direction the condition is termed as
A. Vexillary
B. Imbricate
C. Twisted
D. Valvate

Answer 1

Hint: Sepals are leaf-like components that surround the bud of the flower. They are located in a flower's lower section. When forming, the sepals fold over and shield the closed bud from weather or wounds. Typically, a flower has either two or five sepals on it. The primary role of petals is to attract hummingbirds and insects so that there can be pollination. The stamen and pistil, the parts of the plants required for reproduction, are also covered by petals.

Complete answer:
Vexillary- A characteristic of the family fabaceae is vexillaire or descending imbricate aestivation. In it, two lateral petals, which in turn overlap two anterior petals, overlap the rear largest petal. It is also called the corolla of papilionacea. If the petals are of various sizes and show a descending imbricate pattern, it is called vexillary, for example, pea.
Imbricate- It is called imbricate if the margins of the sepals or petals overlap each other without any specific direction. Example- Cassis
Twisted- It is called twisted, for example, China Rose, if the margins of the sepals or petals overlap each other frequently in the same direction.
Valvate- It is called valvate, such as Calotropis, when the margins of the sepals or petals do not overlap each other. Valve Added to the arrangement (aestivation) of a flower bud of sepals or petals in such a way that these parts meet and do not overlap at their edges. Where they overlap, imbricate is known as the aestivation.

Hence, the correct answer is (B).

Note:
A special type of aestivation occurring in plants such as peas is vexillary aestivation. In this form of estivation, two smaller petals are enclosed by a wide petal called norm. Phyllotaxy, the arrangement of a leaf or bud along a plant stem in relation to another leaf or bud, is a useful basis for plant classification.