Gymnosperms are heterosporous, i.e., producing microspores and megaspores. Gametophytic generation (n) is much reduced. The first male gametophytic cell is microspore or pollen grain. The first female gametophytic cell is functional megaspore that produces nuclear and later cellular female gametophyte. In gymnosperms, megaspores remain permanently in the megasporangium and produce female gametophyte within the megasporangium (nucellus). The male and female gametophytes in gymnosperms do not have an independent free-living existence.