The key difference between actinomorphic and zygomorphic flower is that actinomorphic flower is a flower that is radially symmetrical and can be divided into two equal parts along any diameter while zygomorphic flower is a flower that is bilaterally symmetrical and can be bisected into two equal parts only in one plane.
Floral symmetry explains whether the flower can be bisected into mirror images. Some flowers are radially symmetrical while some flowers are bilaterally symmetrical. However, some flowers are asymmetrical. Flowers with radial symmetry can be bisected into identical halves along any diameter. Those flowers are called actinomorphic flowers. In contrast, flowers with bilateral symmetry can be bisected into two identical halves in only one plane. Those flowers are called zygomorphic flowers.
CONTENTS
1. Overview and Key Difference
2. What is a Actinomorphic Flower
3. What is a Zygomorphic Flower
4. Similarities Between Actinomorphic and Zygomorphic Flower
5. Side by Side Comparison – Actinomorphic vs Zygomorphic Flower in Tabular Form
6. Summary
What is an Actinomorphic Flower?
An actinomorphic flower is a flower that can be divided into three or more identical sectors along any diameter or any vertical plane. Many flowers are actinomorphic. They are radially symmetrical and star-shaped regular flowers. Floral organs of actinomorphic flowers are equal in size. Hence, they are regular flowers.
Figure 01: Actinomorphic Flower
When bisected in any diameter, actinomorphic flowers give two identical halves. Romulea rosea flowers are actinomorphic flowers. Furthermore, lily (Lilium, Liliaceae) and buttercup (Ranunculus, Ranunculaceae) flowers are also actinomorphic flowers. Actinomorphic flowers are a basal character of angiosperms.
What is a Zygomorphic Flower?
A zygomorphic flower is a flower that can be divided into two mirror images by only a single plane. Similar halves can be obtained from only one vertical plane. These flowers are bilaterally symmetrical. Zygomorphic flowers have floral parts which are unequal in size. The corolla especially has unequal size petals, so they are irregular flowers.
Figure 02: Zygomorphic Flower
Gladiolus flower (Iridaceae) is one example of a zygomorphic flower. Moreover, orchids and flowers of most members of the Lamiales are zygomorphic flowers. Zygomorphic flowers are a derived character of angiosperms. There are three types of zygomorphic flowers as typically zygomorphic, transversely zygomorphic and obliquely zygomorphic.
What are the Similarities Between Actinomorphic and Zygomorphic Flower?
- Actinomorphic and zygomorphic flowers are two types of flowers based on their symmetry.
- Both types of flowers give mirror images when bisected.
What is the Difference Between Actinomorphic and Zygomorphic Flower?
Actinomorphic flowers give two similar halves when bisected along any diameter. In contrast, zygomorphic flowers produce two mirror images when bisected in only one plane. So, this is the key difference between actinomorphic and zygomorphic flower. Actinomorphic flowers have equal size floral parts while zygomorphic flowers have unequal size floral organs. Moreover, actinomorphic flowers are regular flowers while zygomorphic flowers are irregular flowers. Roses, lilies, and buttercups are examples of actinomorphic flowers while orchids are an example of zygomorphic flowers.
The following table summarizes the difference between actinomorphic and zygomorphic flower.
Summary – Actinomorphic vs Zygomorphic Flower
Actinomorphic flower is a radially symmetrical flower. It produces mirror images when bisected along any vertical plane. In contrast, zygomorphic flower is a bilaterally symmetrical flower. It produces two mirror images only from one vertical plane. Thus, this is the key difference between actinomorphic and zygomorphic flower. Zygomorphic flower has unequal size flower parts while actinomorphic flower has equal size flower parts, especially petals. Therefore, actinomorphic flowers are regular flowers, while zygomorphic flowers are irregular flowers.
Reference:
1. “Floral Symmetry”. En.Wikipedia.Org, 2020, Available here.
Image Courtesy:
1. “Actinomorphic” By Flickr (CC BY 2.0) via Commons Wikimedia
2. “3249463” (CC0) By Supana via Pixabay
