In the female strobiles (cones) there are megasporophylls (fertile leaves of the strobile) that contain megasporangia. In the megasporangium the spore mother cell undergoes meiosis generating four haploid cells of which three regress and one gives birth to the functional megaspore. The functional megaspore by several mitosis forms the female gametophyte that contains the oospheres (female gametes) of the plant. The female gametophyte is located within the megasporangium that has a small opening, the micropyle, through which the pollen tube enters.
The process is related to the diplobiontic life cycle (alternation of generations) since the functional megaspore generates the haploid stage of the plant (the female gametophyte).