Whorls of a flower are circular sections of a flower with a common centre. When a flower is seen from the top its whorls can easily be distinguished. A flower is made up of four whorls:
- The outermost whorl is known as the Calyx and comprises of the sepals.
- The second whorl comprises of the petals and is known as the Corolla.
- The Stamens and Carpels constitute the inner whorls that contain the reproductive organs of a flower.
The calyx is the outermost whorl of a flower. It comprises of sepals, tiny leaves present at the base of a flower. These protect the flower whorls against mechanical injuries and dessication.
Some plants have coloured sepals the calyx and are called petaloids.
If the sepals are free the calyx is called polysepalous, and if they are united it is called gamosepalous.
In many flowers, the sepals fall off before the flower even opens fully. Such sepals are known as caducous.
In some, the sepals fall off after fertilization. Such sepals are known as deciduous.
The persistent sepals remain up to the fruiting stage.
This is the second whorl of a flower. It contains petals which serve two main functions:
- To protect the reproductive parts of a flower
- To attract pollinators.
They are brightly coloured and scented to attract animals and insects for pollination. The calyx and corolla are collectively called the perianth.
Different forms of the corolla are found in the flowers.
- Polypetalous Regular
- Polypetalous Irregular
- Gamopetalous Regular
- Gamopetalous Irregular
Corolla contains long projections and outgrowths that enhance the beauty of the flower.
Also read: Flower- Parts of a Flower
Stamen is also known as the third whorl of the flower and is the male reproductive part. It consists of a filament which is a thread-like structure with a circular structure anther on the top. Pollen is produced by the anther which contributes to the male reproductive process of the plant. All the stamens do not bear fertile anthers.
The carpel is the fourth whorl of the flower present in the centre. The carpels contain the pistil, the female reproductive part of the flower. It comprises of the ovary, style, and stigma. The egg or the ovule is present in the ovary. After fertilization, sometimes the ovary turns into the fruit to keep the seed. At the top of the ovary is a vertical structure called style that supports the stigma. The dispersed pollens stick to the stigma and travel down to the ovary through the style.
Also read: Flowers and Inflorescence
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