Phylogeny and diversity of the Auricularia mesenterica (Auriculariales, Basidiomycota) complex

Samples of the so-called Auricularia mesenterica complex from Europe, China, and Brazil are studied, and two new species, A. orientalis and A. brasiliana, are described from the species complex based on both morphological characters and molecular evidence. Phylogenetic analysis by combined ITS, nLSU, and rpb2 sequences shows that Auricularia mesenterica, A. orientalis, and A. brasiliana are closely related as a monophyletic clade. However, Auricularia mesenterica has longer and narrower basidiospores (14-17x 4.7-5.2 mu m) and a distribution in Europe. A. orientalis has shorter and wider basidiospores (12.5-14.2x5-6 mu m), and is found in China so far. A. brasiliana has hyphae distinctly inflated in KOH (up to 13 mu m), the shortest basidia in the complex (30-47x3-5 mu m), and was discovered in Brazil. Illustrated descriptions of the two new species are given based on the materials in the present study.