A flower is a specialised and condensed reproductive shoot of flowering plants that possess essential reproductive parts. The flower possesses four whorls. They are calyx, corolla, androecium and gynoecium.

In sexual reproduction two gametes fuse together to form a zygote, which later develops into a mature organism. These gametes are known as sex cells or germ cells or reproductive cells. These sex cells are of two types: Male sex cells and Female sex cells.

The flower is the reproductive organ of the plant. The receptacle is the upper portion of the flower stalk. The base of the flower with it and all the parts of the flower are attached to the receptacle. The receptacle is also called as thalamus.