Concept: This question tests your understanding of flower symmetry, specifically identifying an example of an actinomorphic flower.

Why (A) Datura is correct: Actinomorphic flowers are those that can be divided into two equal radial halves by any radial plane passing through the center. This type of symmetry is also known as radial symmetry. Datura (thornapple) exhibits radial symmetry, meaning its flower parts are arranged symmetrically around a central axis.

Why other options are wrong:

• (B) Cassia: Cassia flowers are zygomorphic (bilaterally symmetrical), meaning they can be divided into two equal halves by only one specific vertical plane.
• (C) Pisum: Pisum sativum (pea) flowers are zygomorphic, characteristic of the Fabaceae family.
• (D) Sesbania: Sesbania flowers are also zygomorphic, belonging to the Fabaceae family.

Common Mistake: Students often confuse actinomorphic and zygomorphic symmetry, especially when examples from different plant families are given.

NEET Tip: Remember that most flowers of the Fabaceae (legume) family are zygomorphic, while many Solanaceae (e.g., Datura, Petunia) and Liliaceae (e.g., Lily) flowers are actinomorphic.

Correct Answer: (A)