Floral Formula MCQ - Practice Questions with Answers

Floral Symmetry, Number of Floral Appendages and Position of Ovary in a Flower

Floral Symmetry: In symmetry, flowers can be actinomorphic, zygomorphic or asymmetric.

1. When a flower can be divided into two equal radial halves in any radial plane passing through the centre,  it is said to be actinomorphic. For example, mustard, datura, chilli, etc.
2. When a flower can be divided into two equal halves in only one particular plane, it is said to be zygomorphic. For example, pae, gulmohar, bean, cassia, etc.
3. When a flower cannot be divided into two equal halves in any plane, it is called asymmetric or irregular flower. For example, canna.
    

Number of Floral Appendages:
A flower may be:

1. Trimerous - floral appendages in multiple of 3
2. Tetramerous - floral appendages in multiple of 4
3. Pentamerous - floral appendages in multiple of 5

Position of ovary in a flower:
Based on the position of calyx, corolla and androecium with respect to ovary on the thalamus, the flowers are described as:

1. Hypogynous Flowers: The ovary occupies the highest position while the other parts are situated below it. The ovary is said to be superior. The thalamus is convex or conical. For example, mustard, China rose, brinjal.
2. Perigynous Flowers: The ovary is situated in the centre and the other parts are situated on the rim at the same level as that of the ovary. The ovary is said to be half-inferior. The thalamus appears cup-shaped or flask-shaped. For example, plum, rose, peach, etc.
3. Epigynous Flowers: The ovary occupies the lowest position while the other parts are situated above it. This occurs because the thalamus becomes hollow flask-shaped and its wall fuses with the wall of the ovary. The ovary is said to be inferior. For example, guava, cucumber and ray florets of sunflower.