The effect of light illumination on sclerotial buoyancy of 15 strains of Sclerotium rolfsii isolated from water chestnut and 27 strains isolated from other host plants was examined. In most strains, sclerotia formed on V-8 agar medium under light exposure tended to float in water, and sclerotia formed in darkness tended to sink. Buoyancy rates of sclerotia varied with exposure time to light during incubation, and in most strains were about 50% or more for 1 h/d illumination, and about 100% for 12 h/d. Microscopic study revealed that the buoyant sclerotia had broader intercellular spaces in sclerotial tissues, and this structural difference was suggested to be an important factor in sclerotial buoyancy.

　An ectomycorrhizal fungus, Lyophyllum shimeji, was cultivated using commercially available culture instruments, and culture conditions for mass production of this mushroom were determined. The results obtained were: (1) Suitable ratio of barley to saw dust as a basal substrate of the medium was 2 : 3 by volume. (2) Addition of inorganic nutrients, especially P and Fe, increased yield of the fruit-body. (3) High yields per volume of the medium were obtained with wide cap bottles filled less than half full with medium. (4) Peat and porous stone (Kanumatsuchi) were good materials for casing at 30-35 days after inoculation. (5) Excellent strains must be selected to cultivate this mushroom commercially, since wild strains showed wide variations in yield and form of the fruit-body. Under the above conditions, 4 strains selected from 60 wild strains produced the average of 123 g/bottle of fresh fruit-body on 650 ml of medium during the average culture period of 81 days.

　Truncatella sp. has two development processes of conidium formation on different media. On PDA, Truncatella sp. formed many conidiogenous cells directly from hyphae. On culture with hortensia leaves, on the other hand, Truncatella sp. formed many conidiogenous cells on acervuli. These results indicate that the characteristic features of Hyphomycetes and Coelomycetes are affected significantly by environment.