A New Species of Marasmius Sect. Globulares Growing in Grassland from Japan

Marasmius neooreades sp. nov. from Japan is described. This species produces fleshy, medium-sized basidiomata that are macromorphologically similar to M. oreades, with a pileus ranging from wheat-colored to dark brown and a tough stipe covered with brownish tomentose squamules. The gill edges bear cheilocystidia that are clavate to diverticulate. The pileipellis is hymeniform and composed of Globulares-type elements containing brown pigments. The species typically occurs gregariously in grasslands and occasionally forms fairy rings. Phylogenetic analyses based on ITS and LSU sequences indicated that M. neooreades forms a well-supported, independent clade distinct from previously described species of Marasmius. In addition, a combination of morphological characters clearly differentiates this species from all described taxa. An illustrated description and the phylogenetic placement of the new species are provided.