Corolla is the overall structure of the petals of a flower taken as a group within the calyx. Normally the corolla is the most conspicuous part of a flower and of a bright colour other than green. The concept of corolla description is widely used in botany as a primary determinant of vascular plant identification. Alternatively the corolla may be considered as the inner whorl of the perianth structure. The role of the corolla in plant evolution has been studied extensively since Darwin postulated a theory of the origin of elongated corollae.[1]