Arbitrarily begin the moss life cycle with the release of spores from the capsule that mounts the mature haploid sporophyte as the operculum drops off. Haploid spores germinate and develop into filamentous protonema . Young gametophyte buds form from which a leafy male or female gametophyte develops. This is the green plant one usually recognizes. The male gametophyte is equipped with an antheridium in which sperm develop and mature.
Eggs develop within the female archegonium .
Upon maturation, raindrops wash sperm from the antheridium and deliver them to the mature, non-motile egg, to which they are chemically attracted. A single sperm fuses with an egg during fertilization to produce a diploid zygote. The zygote undergoes mitosis to form the sporophyte, consisting of a capsule sitting astride an erect, stem-like seta . The sporophyte is usually brown at maturity, indicative of its lack of chlorophyll and inability to photosynthesize. Consequently, the sporophyte is wholly dependent upon the haploid gametophyte for its sustenance.