A megagametophyte develops with an egg cell within it that develops into an embryo through parthenogenesis.
From the en.wikipedia.org
After pollination, a tube grows from the pollen through the stigma into the ovary to the ovule and two sperm are transferred from the pollen to the megagametophyte.
From the en.wikipedia.org
The central cell of the megagametophyte may require fertilization to form the endosperm, pseudogamous gametophytic apomixis, or in autonomous gametophytic apomixis fertilization is not required.