It is the tissue where the integuments and nucellus are joined. Seeds consist of an endosporic megasporangium surrounded by one or two sheathing layers (integuments). The ovule appears to be a megasporangium with integuments surrounding it. Gymnosperms typically have one integument (unitegmic) while angiosperms typically have two integuments (bitegmic). In plant ovules, the chalaza is located opposite the micropyle opening of the integuments. Surrounding the megagametophyte are (one or) two integuments, which form an opening called the micropyle. The seed coat develops from the maternal tissue, the integuments, originally surrounding the ovule. Three days before adults emerge, developing parasite spores can be seen through their pupal integuments. The integuments develop into the seed coat when the ovule matures after fertilization.