The standard petal of a papilionaceous corolla is also called

Explanation

(a) : The posterior large bilobed petal of a papilionaceous corolla is called standard or vexillum. It overlaps the two smaller lateral petals known as wings or alae. Therefore, the correct answer is Vexillum. The vexillum is the large, upper petal of a papilionaceous corolla, and it is also called the standard petal. The corona is a ring of fused petals, and the carina is the two lowest petals of a papilionaceous corolla.