During the micro gametogenesis the nuclear division results in the formation of the asymmetric cells. It forms the larger vegetative cell and the smaller generative cell. The vegetative cell is naked and occupies a major part of the pollen grain. The generative cell is small in size it later becomes elongated and appears vermiform. This shape helps the generative cell for the movement into the pollen tube. The generative cells give rise to the male gametes or the sperm.