The two morphologically similar species of mushrooms, i.e., Neoalbatrellus yasudae (Lloyd) Audet from Japan and N. odorus Yuan Y.Chen & B.K.Cui from China were extensively compared based on macromorphological characters and molecular data. The results clearly indicated that some key morphological characters, such as cap color and pore sizes, cannot reliably separate the Japanese and Chinese materials. Phylogenetic trees based on the ITS and nuclear large subunit of ribosomal DNA sequences also indicated that these two species should be considered a single species. We therefore propose that N. odorus is a later synonym of N. yasudae, and an emended description of macroscopic characters of the species is provided.

Although it is known that flowering onset is strongly influenced by temperature in Rosaceae, there was a lack of research on whether the effects of temperature differ among regions within the same species. In this study, we used flowering records of Kerria japonica from four sites—Fukushima, Ibaraki, Toyama, and Yamagata—recorded between 2003 and 2020 by the Tsukuba Botanical Garden and the Japan Meteorological Agency to compare the correlation between flowering onset dates and cumulative temperature across regions. As a result, two key findings emerged: (1) flowering onset trends were inconsistent across sites, with advanced trends were observed only in Fukushima and Ibaraki, and (2) flowering onset at all sites was strongly correlated with cumulative temperature, but the accumulation periods varied, being longer in lower-latitude regions. It was suggested that meteorological differences and temperature requirements for flowering may affect the variability of flowering onset dates between sites.

The altitudinal and latitudinal distributions of Shortia rotundifolia sensu lato were compared between the Ryukyus of Japan and Taiwan. A significant difference in altitude values was found between the Ryukyus and Taiwan, and confirmed asymmetry of the distribution altitude of this species previously suggested. In addition, a negative correlation was found between altitude and latitude values in a region of the Ryukyus and Taiwan. Molecular phylogenetic analysis based on single-nucleotide polymorphism data revealed two major clades comprising plants from Amami and Okinawa Islands of the Ryukyus, and from Iriomote Island of the Ryukyus and Taiwan. The latter clade included two subclades—one consisting of plants from Iriomote Island and the northern part of Taiwan, and another consisting of plants from central and southern Taiwan. These results suggested that the high mountain range between the northern and central parts of Taiwan likely acts as a biological barrier for this species.

The botanical specimen collection by Hideo Koidzumi, acquired by the National Museum of Nature and Science in 1953 and has not yet completed registration, was overviewed by analyzing 20,936 databased specimens. Based on the serial numbers assigned to each specimen, the total number was estimated to be about 110,000, with approximately 40,000–45,000 specimens having been registered in the herbarium of the museum by the end of 2024. Seventy-eight percent of the total number was collected by himself, and 70% of them were collected in Nagano Prefecture and Hokkaido Prefecture. The number of collectors other than Koidzumi was over 300 including regional botanists of various areas of Japan who were active at the time, as well as Koidzumi’s students.