Nucellus is the wall of megasporangium and the part of ovule in which embryo sac develops. Nucellus provide nutrition to the growing embryo and also protects the embryo. Chalaza is the portion of ovule which is opposite to the region of attachment of nucellus, integuments and funicle. Micropyle is a small opening covered by the integuments and it is the site of entry of pollen tube during fertilisation. Hilum is a structure by which the body of ovule is attached to the funicle.