Phylogeny and taxonomy of Echinodontium and related genera.

The phylogenetic relationship of eight species of Echinodontium, Laurilia, and Perplexostereum of Russulales were analyzed based on sequences of the nuc rDNA ITS1-5.8S-ITS2 (ITS [internal transcribed spacer]) and D1-D2 domains of nuc 28S rDNA (28S). Our results show that Echinodontium tinctorium, E. ryvardenii, and E. tsugicola represent Echinodontium sensu stricto. Based on morphological and phylogenetic evidence, the new genus Echinodontiellum is established to accommodate Echinodontium japonicum. Amylostereum, Echinodontium, Echinodontiellum, and Larssoniporia form the Echinodontiaceae clade. The Bondarzewiaceae clade includes Bondarzewia, Heterobasidion, Laurilia, and Lauriliella. The new genus Lauriliella is established for the species initially described as Stereum taxodii and Lauriliella taiwanensis new to science. The monotypic genus Perplexostereum forms a distinct clade. A key to the genera in the Echinodontiaceae and Bondarzewiaceae as well to Perplexostereum is provided.