Two new species and one new combination of Agaricales from Japan

Two new species and one new combination of Agaricales are described and illustrated from eastern Honshu, Japan, and Ishigaki Island, southwestern Japan: (1) Gymnopus oncospermatis comb. nov. (subsection Vestipedes of section Vestipedes), new to Japan, has pale brown to whitish, collybioid basidiomata with very close lamellae, and forms a distinct white extensive mycelial mat on the dead leaf bases of the palm Satakentia liukiuensis in Ishigaki Island; (2) Hydropus aurarius sp. nov. (subsection floccipedes of section floccipedes), forming clitocyboid basidiomata with a dark brown furfuraceous pileus and stipe and vivid yellow lamellae, found on fallen dead twigs in oak forests; and (3) Tylopilus castanoides sp. nov. (section Oxydabiles), forming medium to large, reddish-brown basidiomata with a minutely scurfy-punctate stipe, found in Carpinio quercion forests.