A new agaricoid species of Porotheleum (Porotheleaceae, Agaricales) from

Porotheleum microsporum, a new agaricoid species of the genus Porotheleum (Porotheleaceae, Agaricales), was found growing on the live bark of Salix babylonica in Quancheng Park (Ji'nan City, Shangdong Province, China). This discovery, a testament to our rigorous research, is described and illustrated based on morphological, molecular, and ecological evidence. Our phylogenetic analyses based on DNA sequences of the internal transcribed spacers 1 and 2 with the 5.8S rDNA (ITS) and the large subunit of nuclear ribosomal DNA (LSU) support the inclusion of this new species in the genus Porotheleum as it forms an independent clade in the phylogenetic tree. Morphologically, P. microsporum differs from any known species by combining a pale-yellow pileus with an ochre-yellow center and relatively small basidiospores.