Q. How is female gametophyte formed in angiosperms?

Into the flower ovary there are megasporangia enclosed by a tegument having a small opening, the micropyle. Inside the megasporangium there is a megasporocyte, or megaspore mother cell, that undergoes meiosis forming four megaspores of which three regress and only one is functional. The useful megaspore undergoes (three) mitosis generating eight cells that as a whole form the embryonic sac.