Four New Species of Sistotrema (Hydnaceae, Cantharellales) from China

Wood-inhabiting fungi play important ecological roles in forest ecosystems by participating in wood decomposition and nutrient cycling and represent a highly diverse group within Basidiomycota. In this study, four new wood-inhabiting species of Sistotrema from China are described and illustrated based on morphological examination and phylogenetic analyses of ITS, nLSU, nuc-SSU, and RPB2 sequence data. Sistotrema armandii is characterized by a hypochnoid hymenial surface, ventricose to suburniform basidia, and long sterigmata. Sistotrema caeruleogriseum is separated by its slightly tuberculate hymenial surface, subclavate to suburniform basidia with 4-sterigmata, and subglobose to globose basidiospores. Sistotrema luteum is typified by angular to irregular pores, thin and slightly fimbriate dissepiments, and globose basidiospores. Sistotrema tenuissimum is distinguished by a farinaceous hymenial surface, a monomitic hyphal system with thin- to slightly thick-walled generative hyphae, and barrel-shaped to suburniform basidia with 4 or 6 long sterigmata. The four new species and their phylogenetically related and morphologically similar species are discussed. This study expands the current knowledge of species diversity and phylogenetic relationships within the genus Sistotrema in China.