Floral Whorls: Calyx:
It is the outermost whorl of a flower.
The individual members of calyx are called sepals.
Generally the sepals are green.
When the sepals are free from one another, it is described as polysepalous calyx,
e.g., Brassica
When they are united or fused with one another, it is known as gamosepalous calyx,
e.g., China rose.
When the sepals fall off as soon as the flower bud opens, the calyx is called caducous
e.g., Argemone (poppy).
The calyx is called deciduous, when it survives till the withering of petals, as in
e.g. lotus, mustard.
Sometimes the sepals remain even after fruit formation. In such a case, calyx is said to be persistent,
e.g., brinjal, pea, etc.
Functions of Calyx:
The main function of the calyx is to enclose the flower in bud condition and to protect the essential organs from injury, rain, etc.
Being green,it can produce food by the process of photosynthesis.
In some flowers, sepals are bright-colored, (petaloid sepals)
- they serve to attract insects for pollination.
Sometimes sepals are modified into hairy structures called pappus;
such pappus calyx is persistent and helps in the dispersal of fruits.
Corolla:
It is the second whorl of flower, which is usually larger in size and inner to calyx.
The individual members of this whorl are called petals.
Generally, the petals are colored and scented.
When the petals are free from one another, corolla is described as polypetalous (Rose).
But when they are united with one another, it is known as gamopetalous (Datura).
Functions of Corolla:
The main function of corolla is attraction.
Being bright in color it attracts insects or birds for pollination.
When scented, that sweet smell attracts the insects.
In gamopetalous flowers,
the lower portion of the tubular corolla may serve to store nectar, which also helps in attraction of agents for pollination.
In bud condition,
the petals protect the inner essential organs, stamens and carpels.
Perianth:
In some flowers calyx and corolla are morphologically similar.
They are together known as perianth and its individual members are called tepals.
Like corolla, perianth is polyphyllous (when tepals are free) or gamophyllous (when tepals are fused).
When the tepals in a perianth are green, it is called sepaloid perianth
when the tepals are brightlycoloured it is described as petaloid perianth.
In monocots mostly perianth is present.
Functions of perianth:
It functions as both calyx and corolla.
It protects the essential whorls of flower in bud condition.
Petaloid perianth helps in attraction of insects for pollination
Sepaloid perianth performs photosynthesis.
