Gametophyte development of a xeric fern was less studied.In present investigation,the gametophyte development of a xeric fern,Gymnopteris vestita was studied using light microscopy.Spores,trilete and brown when matures,germinate at about 10～15 d after sowing.The spore germination pattern is the Vittaria-type.The prothallial cell firstly develops into the uniseriate filaments.And the subsequent development differs greatly from the non-xeric ferns.The most obvious feature of the gametophyte development is producing abundant branches.In most cases,the filaments can produce filamentous branches by longitudinal divisions of the basal cells of the uniseriate filaments.These branches may further branch several times.The terminal end of the branches can form plates.And these plates can also produce filaments or plates.Finally,the gametophytes form cluster colony.In a few cases,the uniseriate filament forms plate directly.However,the plates do not develop into prothallus,but form plenty of filamentous branches.At the cluster stage,numerous antheridia occur in the filaments and surface of the plate.No archegonia are discovered at artificial culture condition.The vegetative growth of the gametophyte last a long time if the culture conditions was suitable.New filaments form continually from the old plates.Apogamous sporophytes are discovered in the large heart-shaped prothallus,which always lie in the outside of the cluster.The features of gametophyte development of G.vestita,including the multi-branched clusters,flourishing vegetative growth of the gametophytes,and apogamy,suggest a xeric adaptation to the reproduction of the ferm G.vestita.