Alternation of generations (also known as metagenesis) this type of life cycle that occurs in those plants and algae in the Archaeplastida and the Heterokontophyta that will have distinct haploid sexual and diploid asexual stages. A multicellular haploid gametophyte with n chromosomes alternates with a multicellular diploid sporophyte with 2n chromosomes is form in these group, made up of n pairs.
A mature sporophyte will produces haploid spores by meiosis, a process which reduces the number of chromosomes to half, from 2n to n.
In the haploid cell the spores germinate and grow into a haploid gametophyte. At maturity, the gametophyte produces gametes by mitosis, which does not alter the number of chromosomes.
