The reproductive organ of a plant is its flower. The four whorls of the flower are the calyx, corolla, androecium, and gynoecium, which are arranged from outer to inner.
The accessory whorls are the two outermost whorls, while the essential whorls are the two inner whorls.
The calyx can be termed as the outer floral whorl, made up of green leaf-like structures called sepals that protect the flower's delicate inner parts.
The second whorl, the corolla, is made up of attractive structures known as petals. Petals are equal in number.
The androecium is the male reproductive part of the flower, which is made up of stamens and is an essential whorl of the flower.
The female reproductive part of the flower, made up of pistil, is known as the gynoecium.