Structure and Function of a Flower
Calyx
The calyx is made up of sepals, which are usually green.
Where the sepals are free, they form a polysepalous calyx.
When the sepals are fused, they form a gamosepalous calyx.
The calyx protects the inner parts of the flower (especially during bud development).
There may be another ring of sepal-like structures just beneath the calyx called epicalyx.
Corolla
It is made up of petals which are brightly coloured, large and conspicuous especially in insect pollinated flowers where they attract insects for pollination.
If the petals are fused, the corolla is said to be gamopetalous.
If the petals are free, the corolla is said to be polypetalous.
Androecium
It is the male part of the flower.
It is made up of one or more stamens.
The stamen consists of two parts, the long stalk-like structure, the filament, which bears the anther at its tip.
The anther consists of four pollen sacs, which contain pollen grains.
These contain the male gametes.
The stamen may be either fused to form a staminal tube, as in the Hibiscus, or they may be free, as in a Crotalaria flower.
