Soil samples collected from Japan, Malaysia, and Norway were incubated with four ectomycorrhizal plants to detect mycorrhizal fungal inocula. All soil samples produced ectomycorrhizal colonization on host plants. Twelve ectomycorrhizal morphotypes were classified in the pine forest soil, four types in birch forest soil, three types in tropical rain forest soil, and one type each in larch forest and tundra soil. These results suggest that diverse ectomycorhizal fungi are easily detectable from sampled soil with baiting host plants.

Two powdery mildew fungi of the genus Erysiphe were first found on Vaccinium and Betula in Japan. The one that colonized on V. oldhamii was identified to be E. vaccinii, and the other found on B. platyphylla var. japonica was identified to be E. ornata var. ornata, respectively.

To develop a reliable method for obtaining monokaryotic strains of an ectomycorrhizal fungus Suillus bovinus, germination rates of basidiospores were compared among combinations of treatments that have been reported to be effective for germination of basidiospores of ectomycorrhizal fungi. Spores of S. bovinus germinated only by the combination of activated charcoal treatment of media and co-culture with seedlings of Pinus densiflora. Abietic acid, which has been reported to be a genus-specific activator of germination for Suillus species, showed no effect, suggesting some other substances contained in root exudates induced germination of spores of S. bovinus.

My studies on fungal successions associated with the decay of pine needles and on biogeography of microfungi inhabiting pine leaf litter are outlined. Results of both studies suggested that the fungi have a distribution pattern similar to that of vascular plants along environmental clines. Methods and techniques to study the distribution of microfungi on macro scales are introduced.

Mycena viridimarginata found in Hokkaido, Northern Japan is described and illustrated. This species is newly recorded from Japan.