ABSTRACTTwo new taxa of marasmioid fungi from California are described and illustrated:Marasmius thiersii(sectionAndrosacei) andMarasmiellus ramealisvar.californicus(sectionRameales). Marasmius quercophilusis reported for the first time from North America.Marasmius copelandiiis redescribed andM. olidusis reduced to a variety ofM. copelandii. Marasmius plicatulusis redescribed and a neotype is designated. Illustrations of salient microscopic characters are provided for all taxa.