A sporulation-deficient (sporeless) mutant of Pleurotus cornucopiae var. citorinopileatus, induced by UV irradiation, was cytogenetically and genetically characterized. The sporeless mutant formed less than 0.1％ of the basidiospores produced by wild-type P. cornucopiae. The sporulation-deficient phenotype was controlled by a single dominant gene. Basidia and basidiospores on the gill surface of the wild-type strain exhibited consistent shape and size. By contrast, the few basidiospores produced by the sporeless mutant were highly variable in length, with some very long spores observed, and spores were often wrinkled and shrunk. Basidia with fewer than four sterigmata were frequently observed. HCl-Giemsa staining revealed aberrant nuclear characteristics in the sporeless mutant, such as nuclear localization in the basidium, abortive basidiospores with no nucleus, and basidia without tetrad sterigma formation during sporulation. This suggested that genes involved in sporulation and basidispore maturation were adversely affected and that the sporulation deficiency was caused by atypical migration of nuclei.

　Macrolepiota mastoidea and Echinoderma echinaceum are reported for the first time from Japan. The former was found on the floor of broad-leaved forests of Quercus or Cryptemeria plantations in Yamanashi, Kanagawa, and Tokyo Prefectures and the latter was found on the floor of mixed broad-leaved and coniferous forests of Mt. Fuji, both during September and October.

　Revised points were outlined for the International Code of Nomenclature for algae, fungi, and plants (ICN; Shenzhen Code 2018) adopted at the Nomenclature Section of the 19th International Botanical Congress (IBC 2017) held in July 2017 at Shenzhen, People’s Republic of China.