Plants have what is called an alternation of generations in their life cycle. The two stages are called the sporophyte generation and the gametophyte generation. The sporophyte generation is diploid (has pairs of chromosomes). It produces spores by meiosis (reduction division), so the spores are haploid (contain only one chromosome from each pair). The spores divide by mitosis to produce a multicellular, haploid gametophyte generation. The gametophyte produces gametes (by mitosis) which fuse during fertilization to form a diploid zygote. This then develops into the sporophyte, completing the life cycle.
