The four fundamental whorls (beginning from the base of the blossom or least hub and working upwards) are as takes after:
Calyx: the furthest whorl comprising of units called sepals; these are commonly green and encase whatever is left of the blossom in the bud stage, on the other hand, they might be missing or unmistakable and petal-like in a few species.
Corolla: the following whorl at the zenith, made out of units called petals, which are normally thin, delicate and colored to pull in creatures that help the methodology of fertilization.