Calyx

Definition of Calyx

Outermost whorl formed by sepals of the flower in angiosperm plants.

There are four whorls of a flower namely calyx, corolla, androecium, gynoecium
Calyx and corolla are the non reproductivenon-reproductive whorls whereas, androecium and gynoecium are the reproductive whorls
The calyx is the outermost non reproductive whorl of the flower
Calyx is formed by units called sepals, that are leaflike structure usually green in colour
The main function of the calyx is to protect the delicate inner whorls in the bud and support it during the opening of the flower
After the full bloom of the flower, it is located at the base of the flower
It protects the flower from desiccation
When the calyx becomes brightly coloured, then it is known as ‘petaloid’
Example: Fuschia plant
When the sepals of the calyx fall off after the opening of the flower, the calyx is termed as caudcous
Example: Argemone
When the sepals are bound to the fruit and do not fall off, then the calyx is said to be persistent
Example: Brinjal
When a whorl of bracteoles is attached to calyx, it is known as epicalyx
Example: Hibiscus

1) Gamosepalous calyx:

In this condition the sepals are partly or completely fused with each other
Example: Flowers of Datura and Hibiscus (China Rose) plant

2) Polysepalous calyx:
In this condition the sepals are free or seperate from each other, the calyx is said to be Polysepalous.
Example : Rose plant.