Among the total 278 genera (comprising ca 1000 species) of Japanese lichens, following 24 genera are designated to have shade species ; Agonimia, Arthonia, Arthopyrenia, Arthothelium, Bacidia, Bysoloma, Chaenotheca, Chiodecton, Chrysothrix, Coenogonium, Collema, Crocynia, Dimeralla, Diploschistes, Enterographa, Flakea, Gaisleria, Japewia, Lepraria, Micarea, Mycocalicium, Pachyphiale, Strangospora, Synalissa. They restrictedly grow in week light condition and in high humidity in various habitats. Taxonomically, they belong to 17 families and 8 orders and thought to be derived from ancestors belonging to different origin.
Most of the Japanese shade lichens are crustose with indistinct thalli and have long been overlooked. During the present study, I have collected ca 1000 species of shade lichens for which extensive taxonomic study were made. As a results, following species are newly found in Japan ; Anisomeridium nyssaegenum, Arthonia spadicea, A.vinosa, Chrysothrix candelaris, Cliostomum friffithii, Enterographa zonata, Flakea papillata, Lopadium disciforme, Maronea constans, Opegrapha gyocarpa, O.varia, Pachyphiale carneola, P.fagicola, Porina Mammillosa, Scoliciosporum chlorococcum, S.umbrinum, Strangospora moriformis.
Most of the species of shade lichens have only few lichen substances or completely lack them. It is noteworthy that shade lichens with chemical substances have only few chemical strains.