Morphological and Phylogenetic Characterization of Three Novel Thaxterogaster (Cortinariaceae) Species from China with an Emphasis on Their Subtropical Distribution

Three new phlegmaciod species of Thaxterogaster, T. borealicremeolinus, T. rufopurpureus, and T. sinopurpurascens spp. nov., from subtropical China were described based on their morphological characteristics and molecular data. Thaxterogaster borealicremeolinus belongs to the sect. Cremeolinae and differs from the other species in this section in its larger basidiospores and its habitat in the Northern Hemisphere associated with Quercus sp. trees. Thaxterogaster rufopurpureus and T. sinopurpurascens belong to sect. Purpurascentes, in which T. rufopurpureus is characterized by a pileus with a reddish-brown coloration when mature and a clavate stipe, while T. sinopurpurascens is characterized by a violet basidiomata, except for a greyish orange to brown pileus, the distinctly marginate bulb of its stipe, and its distribution in subtropical China. The phylogenetic analyses were performed based on nrITS, and detailed descriptions of the new species are provided herein.