The development of the male gametophyte inside an anther is given as:

1. Inside the anthers, meiosis produces four haploid spore cells called pollen spores.
2. The nucleus of each pollen spore divides. The pair of nuclei and their surrounding cell wall are the male gametophyte.

The development of the female gametophyte inside a single ovule is given as:

1. Inside the ovule, a single diploid cell undergoes meiosis, producing four haploid cells. Three of the four cells disintegrate.
2. The remaining cell undergoes mitosis, producing eight nuclei.
3. The eight nuclei and the surrounding membrane are called the embryo sac. This is the female gametophyte.