The sexual reproduction in Spirogyra occurs by conjugation. The conjugation is of two types i.e., lateral and scalariform. Lateral conjugation involves two adjacent cells of a filament (homothalic). The two cells acting as gamctangia and show the formation of amoeboid gametes. A perforation develops in the septum which form conjugation canal. Now the male gamete moves into the female gametangia through the conjugation canal and fuse with the female gamete to form the zygospore. The scalariform conjugation involves two filaments of Spirogyra and takes place between two recently formed cells. The .cell of one filament show the formation of papilla towards. the other filament as a result conjugation canal is formed. The male gamete moves to female gametangium and fuse with female gamete to form zygospore.