Cycas shows a distinct alternation of sporophytic (2n) and gametophytic generations.
Plant body represents sporophytic generation while gametophytes (male and female) are very much reduced.
Male gametophyte is represented by the pollen tube with persistent prothallial cell and sperms. The female gametophyte is represented by the endosperm tissue having archegonia.
The sporophytic generation begins from the oospores which is formed after fertilization of the egg by a sperm.