Question

Keel is the characteristic of the flower-
A. Beans
B. Cassia
C. Gulmohar
D. Calotropis

Answer 1

Hint: It is an innermost fused petal, a characteristic feature of the flower of family Papilionaceae.

Complete answer:
The keel is the petal, where the bottom two petals, below the wings, in flowers of the family Papilionaceae of the flowering plant, sometimes they join to form a structure whose shape also resembles the keel of a boat.
The keel is generally found in the flowers of beans, peas, grams, etc. of the family Papilionaceae.

Additional information:
- The flower of the family Papilionaceae has a butterfly-shaped corolla.
- The outermost petals of these flowers are the largest and are called vexillum or standard.
- The two anterior petals are called keel which fused enclosing stamens and carpels.
- The keel is the innermost petal, also called as Carina.
- These flowers have generally vexillary (overlapping) aestivation (arrangement of flower parts).
- Keel generally keeps the reproductive organs hidden away from insects.
- Petals are modified leaves that surround the reproductive parts of the flowers. Together all the petals of a flower are called a corolla.
- Petals are usually accompanied by another set of special leaves called sepals.
- These sepals collectively form the calyx and lie just below the corolla.
- Petals are often brightly colored or unusually shaped to attract pollinators.

So, the correct answer is Beans.

Note: Keel occurs in humans also which is called a sagittal keel. It is a thickening of part or all of the midline of the frontal bone, or parietal bone where they meet along the sagittal suture, or on both bones.