In angiosperms, functional megaspore develops into Embryo sac, Pollen sac, Endosperm, Ovule.

In angiosperms or flowering plants, the megasporocyte produces a megaspore that develops into an embryo sac through two distinct processes megasporogenesis (formation of the megaspore in the nucellus, or megasporangium), and megagametogenesis (development of the megaspore into the embryo sac, or megagametophyte).