0In Gymnosperms seed are not covered as an ovary does not enclose the ovule.
Ovarian wall =friut wall (after fertilisation)
Ovule has nucelus(2n) nutririvn tissue and one integument.
One cell of nucleus get modified, and form Megaspore mother cell (2n) which by meiosis form 4 megaspore(n), 4 out of 3 disintegrate and one remain functional.
Functional Megaspore germinates inside ovule and forms female gametophyte(n).
Female gametophyte has Archegonia with egg. After pollination (anemophily;wind) fertilisation takes place. The egg develops into zygot-embryo-seed (2n).
The persistent female gametophyte (n) is now called endosperm. Therefore it is haploid(n).
Gymno seed = three generations ( persistent nucleus is parent sporophyte, the endosperm is persistent gametophyte and embryo is future sporophyte).
