Our understanding of the taxonomy and phylogeny of early diverging fungi has dramatically changed during the past 20 years. Early diverging fungi are comprised of the former Zygomycota, Chytridiomycota sensu lato, and the recently established group, Opisthosporidia. These lineages are pivotal to investigating the origin and early evolution of fungi. This review discussed the history and recent advances of taxonomic and phylogenetic studies of early diverging fungi, focusing on the Chytridiomycota sensu lato and Opisthosporidia lineages.

In this study, we described the characteristics of mycelial growth and wood decay of Chorioactis geaster, listed on the 2020 Red List of the Ministry of the Environment, Japan, as an “endangered species Ⅱ (Vulnerable)”. We attempted to produce fruiting bodies by wood-log cultivation of this species. Mycelia grew from 4℃ to 38℃ on a PDA medium, resulting in an optimum temperature of approximately 30℃. The effects of environmental and other factors involved in wood decay were analyzed using linear mixed-effects models. The model selection results showed that the specimens' mass loss was affected by the tree species, incubation temperature, and incubation period and that the density of the bed-log was affected by the duration of cultivation. When the first fruiting bodies developed from Quercus gilva bed-logs in the fall of the 7th y after inoculation, the density and mass loss of the sapwood were approximately 0.62 g/cm³ and 15％, respectively. The fruiting bodies continuously developed for several years, and the hymenium surface of some of the fruiting bodies was uncovered owing to the dehiscence procedure. We concluded that wood-log cultivation may be an effective method for ex-situ conservation of this species.

The Japanese ear-pick fungus known as “Matsukasatake” grows on cones of Pinus species and has long been identified as Auriscalpium vulgare. The authors re-examined Matsukasatake and identified this fungus as A. orientale described from China. Scanning electron microscopy revealed that the spore morphology of Matsukasatake was similar to that of A. orientale. Phylogenetic analysis of nrDNA ITS and LSU regions showed that Matsukasatake and A. orientale belong to the same clade. In addition, Matsukasatake was found on the cones of the genus Pinus subgenus Pinus section Pinus. This is consistent with the reported substrate preference of A. orientale.

We report the first record of Russula granulata in Japan, based on morphological characteristics and phylogenetic positions of the specimens collected in mixed subalpine forests in Nagano Prefecture. The species was characterized by a medium-sized fruiting body that is grayish orange to reddish-brown, a strongly viscid pileus with yellowish-red to reddish-brown centers, and a whitish stipe that exhibits light brown discoloration on the lower half. Phylogenetic analyses showed that the Russula specimens from Japan placed within a clade comprising R. granulata from North America and Eurasia.