A mature male gametophyte is formed from pollen mother cell by

A mature male gametophyte is formed from pollen mother cell by one meiotic division and two meiotic divisions.
At maturity, the male gametophyte consists of three cells, the vegetative cell and the two sperm cells, which lie within the cytoplasm of the vegetative cell.
The male gametophyte develops and reaches maturity in an immature anther. In a plant's male reproductive organs, the development of pollen takes place in a structure known as the microsporangium.