Chinese cabbage roots colonized by the dematiaceous fungal taxon Heteroconium chaetospira were previously found to become highly resistant to clubroot and Verticillium yellows. The dematiaceous fungus possesses an endophytic nature, but no detailed anatomical studies on endophyte–host plant interactions have so far been provided. Light and electron microscopy revealed that hyphae of H. chaetospira were abundant on and inside the root epidermal cells by 3 weeks following inoculation. The penetration pegs easily breached into epidermal cells, and the infection hyphae penetrated into cortical cells. Some appressorium-like swollen structures formed from intracellular hyphae, but no visible degradation of the host cell walls was evident where the hyphae contacted. No visible signs of host reactions and no invagination of the host plasma membrane around the hyphae were seen in the host cells. By 8 weeks following inoculation, masses of closely packed fungal cells had been formed in some cells of the epidermis and cortical layers, but further hyphal ingress was halted, mostly in the inner cortical cell layer. Thus, root vascular cylinders remained intact.

Two new species of Agaricales are described and illustrated from Yaeyama Islands, southwestern Japan: (1) Amanita rubromarginata sp. nov. (section Caesareae Sing. ex Sing. in the subgenus Amanita), forming brownish-orange then reddish-yellow pileus, a pale yellow, squamulose stipe with a thin, membranous, reddish-orange annulus and a thick, saccate volva, and reddish-orange marginate lamellae, found in oak forests of Ishigaki Island; and (2) Tylopilus obscureviolaceus sp. nov. (section Tylopilus), having dark purple basidiomata, white, bitter, unchanging flesh, and a finely purplish-reticulate stipe, found in oak forests of Iriomote Island.

Four Phaeosphaeria species on bamboos are reported. Leptosphaeria lelebae on culms of Bambusa multiplex is synonymized with P. oryzae. A Phaeosphaeria sp. on leaves of Sasa kurilensis is noted to have some similarities to Leptosphaeria sasae. Cultural characteristics of P. brevispora collected from culms of Sasa sp. are first recorded. Phaeosphaeria bambusae on leaves of Pleioblastus simoni is redescribed. In addition, the history of taxonomic studies on bambusicolous fungi in Japan is briefly reviewed.

To investigate the function of amylases in the fruit-body formation of an ectomycorrhizal fungus, Lyophyllum shimeji, we purified the extracellular amylase in the medium of this fungus. The purified enzyme was obtained from 1.7l stationary culture filtrate, with 4.2% recovery, and showed a single protein band on SDS-PAGE. The molecular mass was about 25kDa. The enzyme was most active at around 40°C and pH 5.0 and stable over pH 4.5–6.5 for 30min at 37°C. This amylase was remarkably activated by the presence of Ca²⁺ ion (7.7 times that of the control), but Ba²⁺ and Ag⁺ completely inhibited the activity. The amylase readily hydrolyzed the α-1,4 glucosidic linkage such as dextrin and amylose A (MW, 2900), converting into glucose, and hydrolyzed the α-1,6 glucosidic linkage of isomaltohexaose and amylopectin. However, the enzyme did not hydrolyze the cyclic polysaccharides. On the other hand, when a low molecular mass amylose A was hydrolyzed by this amylase, β-anomer glucose was produced. From these results, we concluded that the amylase from L. shimeji seems to be a glucoamylase.

One new hyphomycete, Phialosporostilbe gregariclava, is described and illustrated based on specimens collected on dead culms of two Sasa species in Hokkaido and Iwate, Japan. This fungus is compared with previously described species of Phialosporostilbe and Nawawia, and its morphological and cultural characteristics are reported.

Cortinarius rubellus is reported for the first time from Japan. It has been found in Yamanashi Prefecture (Mt. Yatsugatake), central Japan, growing in subalpine coniferous forests from August to September. A description and illustrations based on the Japanese material are given.