The calyx is the outermost whorl of the flower and the members are called sepals. Generally, sepals are green, leaf-like and protect the flower in the bud stage. The calyx may be gamosepalous (sepals united) or polysepalous (sepals free).
Corolla is composed of petals. Petals are usually brightly colored to attract insects for pollination. Like calyx, corolla may be also free (gamopetalous) or united (polypetalous). The shape and colour of corolla vary greatly in plants. Corolla may be tubular, bell-shaped, funnel-shaped or wheel-shaped.