The Alternation of phases (or generations) escribes the life cycle of plants, fungi and protists. A multicellular diploid phase alternates with a multicellular haploid phase. The term can be confusing for people familiar only with the life cycle of a typical animal. A more understandable name would be "alternation of phases of a single generation" because we usually consider a generation of a species to encompass one complete life cycle. The life cycle of organisms with "alternation of generations" is characterized by each phase consisting of one of two distinct organisms: a gametophyte (thallus (tissue) or plant), which is genetically haploid, and a sporophyte (thallus or plant), which is genetically diploid. A haploid plant of the gametophyte generation produces gametes by mitosis. Two gametes (originating from different organisms of the same species or from the same organism) combine to produce a zygote, which develops into a diploid plant of the sporophyte generation. This sporophyte produces spores by meiosis, which germinate and develop into a gametophyte of the next generation. This cycle, from gametophyte to gametophyte, is the way in which all land plants and many algae undergo sexual reproduction.