$A-Nucellus, B-MMC, C-Nucellus, D-Megaspore diad $Development of Female Gametophyte $1$. Megaspore mother cell undergoes the reductional/meiotic division that give rise to four megaspores $2$. Three of them die (in majority of plants) only one remains viable. This method of embryo sac formation is called monosporic development $3$. The nucleus of the functional megaspore divides mitotically to form two nuclei, which move to the opposite poles forming two nucleate embryo sac $4$. Two more sequential mitotic nuclear divisions results in the formation of four nucleate and later $8$ nucleate stages of embryo sac After the $8$ nucleate stage cell walls are laid down leading to the organization of typical female gametophyte