Taxonomy and Phylogeny of Amylocorticiales (Basidiomycota): Two New Genera, Six New Species, and Four New Combinations

Amylocorticiales forms a well-supported clade within Agaricomycetes, Basidiomycota, and most of the species have resupinate basidiomes and cause brown rot on wood. It is one of the smallest orders of the basidiomycetes, with the species diversity and phylogeny being understudied. In the present study, we conduct phylogenetic analyses based on the concatenated ITS + nLSU sequence dataset of the order with an emphasis on the samples from southern China. As a result, ten new lineages were found. Combined with the morphological evidence, two new genera and six new species are described and illustrated, and four new combinations are proposed. Amylophanerochaete hainanense gen. et sp. nov. is closely related to Serpulomyces but differs in having smooth hymenophores with rhizomorphs and narrowly cylindrical to slightly sigmoid amyloid basidiospores. The new genus Pseudoathelia is proposed to accommodate Leptosporomyces linzhiense and Athelia septentrionalis, two athelioid species. Four new species, viz. Amylocorticium athelioides, A. bisporum, A. guangxiense, and A. luteolum, collected from southern China, formed distinct lineages within the Amylocorticium clade. Serpulomyces borealis, the only species of the genus, is proven to be a species complex, while one new species, S. subborealis, and two new combinations, S. rhizomorphus and S. yunnanensis, transferred from Ceraceomyces, are found in the lineage. An identification key to all the known genera is provided.