Difference between Actinomorphic and Zygomorphic Flowers (2024)

Floral Symmetry

It describes how a floral part can be sectioned into two or more identical parts. The floral part here includes the perianth – petals, sepals and/or tepals. Based on floral symmetry, the flowers can be –

Actinomorphic
Zygomorphic
Asymmetric

Actinomorphic Flower

Most flowers show radial symmetry and are termed actinomorphic flowers. They can be divided into two equal halves in any plane passing through the centre. Examples – Buttercups, Lily.

Zygomorphic Flower

Zygomorphic are bilaterally symmetrical flowers. These flowers are divided into two equal halves along a single vertical plane. Their floral parts are usually unequal in size. Examples – Jasmine, Orchids.

Difference between Actinomorphic and Zygomorphic Flowers

Actinomorphic Flower	Zygomorphic Flower
They include radially symmetrical flowers.	They include bilaterally symmetrical flowers.
It is a basal character of angiosperm.	It is a derived character.
Two identical sections are obtained along any plane.	Two identical sections are obtained in a single vertical plane.
Their floral parts are equal in size.	Their floral parts are usually unequal.
They are termed regular flowers.	They are irregular flowers.
Examples – Mustard, chilli.	Examples – Pea, Cassia, Bean.

Frequently Asked Questions

What is a peloric flower?

It is an aberration that produces actinomorphic flowers instead of zygomorphic. The genetic control for floral symmetry lies with the cycloidea gene. Knocking out of this gene can produce peloric flowers. Example – Peloric Antirrhinum (snapdragon).

What are asymmetrical flowers?

These flowers do not show any symmetry along any plane. Examples – Canna indica (Indian shot) and the Valerian herb.

What is a tepal?

The tepals form the perianth of a flower. When the perianth is undifferentiated, it cannot be classified into petals or sepals. Thus, the term tepals are used.