In pteridophytes, the main plant body is a sporophyte that is differentiated into true roots, stem, and leaves. The sporophyte bears sporangia, which are subtended by leaf-like appendages called sporophylls. These sporangia produce spores through meiosis in spore mother cells. The spores germinate to form small, inconspicuous, multicellular, free-living, and mostly photosynthetic thalloid gametophytes known as prothallus. The gametophyte bears male and female sex organs called antheridia and archegonia, respectively. Water is essential for the transfer of antherozoids (male gametes) released from the antheridia to the mouth of the archegonium. Fusion of the male gamete with the egg present in the archegonium results in the formation of a zygote. The zygote subsequently develops into a multicellular, well-differentiated sporophyte, which is the dominant phase in the life cycle of pteridophytes.