Tricholoma alpinum, sp. nov., under five-needle pines in alpine and subalpine zones in Japan

Alpine regions in Japan are characterized by the Siberian dwarf pine, Pinus pumila. Although these regions are conserved as national parks due to their unique biome, few reports of the fungal biota are available. We examined mushroom fungi under such vegetation and found a unique yellowish-capped Tricholoma species. Multilocus molecular phylogenetic analyses and morphological observation of specimens showed that the Tricholoma species is very similar to T. fumosoluteum known in North America. The Japanese yellowish-capped T. aff. fumosoluteum had larger basidiospores and basidia and shorter pileipellis hyphae compared with T. fumosoluteum. Therefore, we describe the Japanese entity as a new species, T. alpinum.