Species diversity and taxonomy of Scytinostroma sensu stricto (Russulales, Basidiomycota) with descriptions of four new species from China

Scytinostroma is species-rich genus in Peniophoraceae, Russulales and has been shown to be polyphyletic. In this study, we performed phylogenetic analyses on the core clade of Scytinostroma based on concatenated ITS1-5.8S-ITS2-nrLSU sequence data. Fifteen lineages including four new species from China, Scytinostromabeijingensis, S.boidinii, S.subduriusculum, and S.subrenisporum, were recognized. The genus Michenera was nested within the Scytinostroma s.s. clade in the phylogenetic tree of Peniophoraceae. Sequences of S.portentosum (type species) and S.hemidichophyticum from Europe formed a strongly supported lineage sister to the S.portentosum sample from Canada. It is supposed that the European “S.portentosum” is S.hemidichophyticum, and the former species is restricted in distribution to North America. Scytinostromaduriusculum is supposed to be a species complex. Samples from Sri Lanka (the type locality) formed a lineage sister to those from China, Thailand and Vietnam (described herein as S.subduriusculum) and two samples from France that might represent an undescribed species. The four new species are described and illustrated, and an identification key to all the 14 Scytinostroma s.s. species worldwide is provided. Until now, seven species of Scytinostroma s.s. have been found in China. Our results increased the knowledge of species diversity and taxonomy of corticioid fungi in China.