Many flowers have symmetry. When the perianth is bisected through the central axis from any point, symmetrical halves are produced, forming a radial symmetry. These flowers are also known to be actinomorphic or regular such as rose, Trillium. When flowers are bisected only by one line that produces symmetrical halves the flower is said to be irregular or zygomorphic such as snapdragon or most orchids.
Types of Flowers:
There are mainly 15 types of flowers in the world:
1. Regular Flower:
When the floral parts of each whorl of a flower are similar in size and shape, the flower is called a regular flower.
Example: China rose, Daturia, etc.
2. Irregular Flower:
When any of the floral parts of any whorl of a flower is dissimilar is size and shape, the flower is called an irregular flower.
Example: Pea, Clitoria Ternatea, etc.
3. Actinomorphic Flower:
A flower that can be divided into two equal and symmetrical halves by any vertical plane passing through the axis is called an actinomorphic flower.
Example: Hibiscus, Solanum, etc.
4. Zygomorphic Flower:
A flower that can be divided into two equal and symmetrical halves by one particular plane only passing through the axis is called a zygomorphic flower.
Example: Pisum, Clitoria, etc.
5. Asymmetric Flower:
A flower that can’t be divided into two equal halves by any vertical plane passing through the axis is called an asymmetric flower.
Example: Canna, Vanda, etc.
6. Complete Flower:
A flower is said to be complete when all four floral whorls are present as in China rose, Pea, Daturia, etc. Complete flowers are always bisexual.
7. Incomplete Flower:
A flower is said to be incomplete when any one or more of the four floral whorls are absent as in Beta sp, Cucurbita sp, gourd, etc.
8. Spiral Flower:
When the floral members are borne spirally on an elongated thalamus, the flower is called a spiral flower.
Example: Paeonia, Eupomatia, etc.
9. Cyclic Flower:
When the floral members of each whorl are borne in a cyclic manner on the comparatively shorter thalamus, the flower is called a cyclic flower.
Example: Hibiscus, Daturia, etc.
10. Hemicyclic Flower:
When the floral members are borne partly in a spiral manner and partly in a cyclic manner on the thalamus, the flower is called a Hemicyclic flower.
Example: Magnolia, Nymphaea, etc.
11. Isomerous Flower:
When the number of floral members in each whorl of a flower remains the same or exact multiple of the same, then the flower is called an isomerous flower.
Example: Chine rose
12. Trimerous Flower:
When the number of floral members in each whorl of a flower is three or multiple of three, the flower is called a trimerous flower. Trimerous Flowers are common in monocotyledonous plants.
Example: Grasses
13. Tetramerous Flower:
When the number of floral members in each whorl of a flower is four or multiples of four, the flower is called a tetramerous flower.
Example: Ixora, Oldenlandia, etc.
14. Pentamerous Flower:
When the number of floral members in different whorls of a flower is five or multiples of five, the flower is called a pentamerous flower. Pentamerous flowers are common in dicotyledonous plants.
Example: China rose, Daturia, etc.
15. Perianth Flower:
In some flowers the calyx and corolla can’t be distinguished. There is only one set of accessory members that can neither be termed calyx nor corolla, the accessory whorl is called Perianth.
Example: Tuberose