Tylopilus callainus, a new species with a sea-green color change of hymenophore and context from the south of China

Tylopilus callainus (Boletaceae, Boletales) is described as a new species from the south of China. It is morphologically characterized by a brown pileus tinged with sea-green, a sea-green color change of hymenophore and context when injured, a stipe with sea-green color on the upper part, and a trichodermal pileipellis with slightly inflated hyphae. Phylogenetic analyses of DNA sequences from partial 28S regions, the nuc rDNA internal transcribed spacer (ITS) and the translation elongation factor 1-alpha gene (TEF1) also confirm that T. callainus forms an independent lineage within Tylopilus s. str. Consequently, a detailed description, color photos of fresh basidiomata and line-drawings of microstructures are presented.