A new species of the genus Aleurodiscus sensu lato (Russulales, Basidiomycota) from Hachijo Island, Japan (original) (raw)

Hachijo Island (known locally as Hachijo-jima), located 287 km south of Tokyo, Japan (33°06ʼN, 139°47ʼE), is a small volcanic oceanic island and part of the Izu Islands. The climate is humid subtropical. In Aug 2010 and Sep 2011, the authors collected several specimens of an undescribed corticoid fungus on dead petioles of Livistona chinensis R. Br. ex Mart. var. subglobosa (Hassk.) Becc. (Arecaceae) planted in gardens and along roadsides at several sites on the island (Supplementary Fig. S1). This fungus is morphologically similar to taxa of Aleurodiscus Rabenh. ex J. Schröt. and related genera (Basidiomycota, Russulales, Stereaceae), except in its basidiospore morphology, which is clearly distinct. Here we describe the fungus as a new species of Aleurodiscus and discuss its phylogenetic position and ecological features. The color and con guration of the hymenial surface and marginal zone were noted based on fresh and dried specimens. In the description, color names in quotation marks refer to Rayner (1970). For microscopic observations, a piece of a dried specimen was sectioned vertically using a razor blade. Sections were mounted in 3% (w/v) KOH, Melzer's reagent (Weresub, 1953), sulphobenzaldehyde reagent (SA) (Boidin, 1951), and distilled water. Microscopic elements of the basidiomata were drawn using a drawing tube (Y-IDT, Nikon Imaging, Tokyo, Japan) attached to the microscope (Eclipse Ni, Nikon Imaging). For each taxonomic element of each specimen, 20 measurements were usually made in Melzer's reagent. Basidiospore surface structure was observed with a scanning electron microscope (SU1510, Hitachi, Tokyo, Japan) under 5 kV accelerating voltage, using dried specimens. Procedures for rehydrating, xing, dehydrating, critical-point drying and sputter coating of the specimens followed Endo et al. (2019). The specimens and cultures examined in this study are deposited at the Tottori University Mycological Herbarium (TUMH) and the fungal culture collection (TUFC), respectively, in the Fungus/Mushroom Re