DENDROLOGY

Detailed explanation-1: -Vexillary or descending imbricate aestivation is a characteristic of family fabaceae. In it, the posterior largest petal (standard) overlaps two lateral petals (wings) which in turn overlap two anterior petals (keel). It is also called pailionaceous corolla.

Detailed explanation-2: -Solution: Type of aestivation in fabaceae family is vexillary aestivation.

Detailed explanation-3: -Vexillary aestivation is a distinctive arrangement in which one giant petal covers the other smaller petals. The vexillum is the bigger petal, while the wings are the two bent petals that are laterally positioned. The two innermost, boat-shaped petals are known as keels in this location. Example: Bean flower.