what does exactly produce egg cell?

[scienceclub]

In the process, megaspore divides by mitosis forming 8 nuclei and then membranes partition into a multicellular female gametophyte --- the embryo sac. So egg cell should be created by megaspore? But in the book says that embryo sac produces female gamete. I'm so confused. Thank you for every answer.

[JackBean]

isn't the female gamete the same as egg?

[scienceclub]

Yes, egg is a female gametophyte. So megaspore produces a female gametophyte

[husseingenelab]

the megaspore is the transition stage between the sporophyte (2n) and the gametophyte (1n).

[kingber]

you can find the answer in the following paper:
Genetic and molecular identification of genes required for female gametophyte development and function in Arabidopsis. Development 132, 603-614