Plant ovules: Gymnosperm ovule on left, angiosperm ovule (inside ovary) on right

The integuments develop into the seed coat when the ovule matures after fertilization.

Ovule with megagametophyte: egg cell (yellow), synergids (orange), central cell with two polar nuclei (bright green), and antipodals (dark green)

In gymnosperms, the megagametophyte consists of around 2000 nuclei and forms archegonia, which produce egg cells for fertilization.