Three new species of Inocybe (Inocybaceae, Agaricales) from Southwestern China

The genus Inocybe (Inocybaceae, Agaricales) is a globally diverse fungal lineage with significant ecological importance. In China, species belonging to Inocybe are widely distributed and exhibit exceptionally high diversity. However, the overall diversity of this genus in the country, particularly in the complex mountainous landscapes of southwestern China, remains severely underestimated. Here, based on morphological evidence and multi-locus (ITS, LSU, and rpb2) phylogenetic analyses, we describe three new species from the area, namely Inocybe subtropicocinnamomea, I. biformis, and I. fulvobasalis. Phylogenetically, I. subtropicocinnamomea is assigned to sect. Inocybe and occurs in subtropical broad-leaved or mixed forests. Inocybe biformis belongs to the smooth-spored temperate boreal clade (STBC) and is uniquely adapted to high-altitude subalpine coniferous habitats above 4000 m. Inocybe fulvobasalis is nested within the I. geophylla group and occurs in temperate broad-leaved and coniferous mixed forests. Detailed morphological descriptions, macroscopic photographs, line drawings, scanning electron micrographs of basidiospores, and taxonomic comparisons with allied taxa are provided for the novel species.