Fluorescence micrograph of a transverse section through the upper part of a moss (Tortula truncata) sporangium. The sporangium is the final stage of moss sporophyte development. Spores are produced as a result of meiotic divisions of archesporial tissue inside the moss capsule. Moss capsules are closed with a lid util they are ripe . Every single haploid spore can germinate into a protonema and start moss gametophyte generation. Observed in ultraviolet (UV) light. Magnification: x200 when printed at 10 x 10 cm.