植物地理・分類学会 = The Society for the Study of Phytogeography and Taxonomy
Abstract
Three petrophyte ferns, Lepisorus thunbergianus and Lemmaphyllum microphyllum（Polypodiaceae）and Crepi-domanes latealatum（Hymenophyllaceae）were compared on the basis of biomorphological, histological and cyto-logical data as well as characteristics of plastid apparatus. They showed xero-, meso-, hygro-, helio-, scio- and cryo-morphous characteristics in combination. Lepisorus thunbergianus was shade tolerant, hydrolabile xeromesophyte, that indicated an intermediate position between homoio- and poikilohydric ferns, an eutroph. Lemmaphyllum microphyllum was shade tolerant, hydrolabile, homoiohydric mesophyte with xeromorphous syn-drome, an oligotroph. Crepidomanes latealatum was a sciophyte, hydrolabile poikilohydric hygrophyte, an oligotroph. They had two alternative strategies of their adaptiogenesis : Lepisorus thunbergianus and Lem. mi-crophyllum performed an enhanced ability of water retention of the tissues and cells and C . latealatum per-formed an ability to endure a deep dehydration of tissues without loss of viability and displayed restoration of the normal hydrature under favorable conditions. They also indicated similar tendency of adaptiogenesis : They were dwarfish, evergreen, showed changes in mesophyll from an increase of cell density and number of cell lay-ers up to reduction in structure ; and secondary poikilohydry and oligotrophy of epilitophytes in function
