(i) Role of calyx: Calyx covers and protects all other parts of flower within a bud.
(ii) Role of corolla: Corolla is also a protective floral member. It protects androecium and gynoecium of a flower.
In some flowers the corolla are colorful. Some other flowers have nectar and scent glands at the base of the corolla. These corolla attract insects towards the flower and these insects help in pollination while visiting flowers.