Question

The term keel is used for
A. Carpel
B. Stamen
C. Petal
D. Sepal

Answer 1

Hint: Keel is mainly found in plants of the Papilionaceae family. It is a part of corolla.

Complete step by step answer:
The flowers of Papilionaceae bear Corolla that are special butterfly-like in shape. It is zygomorphic and irregular.
The flowers are bilaterally symmetrical with the corolla consisting of five petals. A single, large, upper petal is known as the vexillum. Two equal and smaller lateral wings are found at the semi cylindrical base of the vexillum. The wings enclose a pair of small keel petals, that are situated somewhat lower than the wings, and are interior to them. They are concave in shape. The two keel petals are fused at their bases to form a boat-shaped structure that encloses the androecium and gynoecium. The aestivation is vexillary. Hence keel is a special type of petal.
The correct answer is option C.

Note: Papillionacae is the family of legume. Crotolaria is another example of a plant that has a butterfly shaped Corolla.