Abstract
A new poroid wood-inhabiting fungal genus, Crassisporus gen. nov., is proposed on the basis of morphological characters and molecular evidence. The genus is characterized by an annual growth habit, effused-reflexed to pileate basidiocarps with pale yellowish brown to yellowish brown, concentrically zonate or sulcate, and velutinate pileal surface, a trimitic hyphal system with clamped generative hyphae, tissues turning to dark in KOH, oblong to broadly ellipsoid, hyaline, smooth, and slightly thick-walled basidiospores. Phylogenetic analysis based on ITS+nLSU sequences indicate that Crassisporus belongs to the core polyporoid clade. The combined ITS+nLSU+mtSSU+EF1-α+RPB2 sequences dataset of representative taxa in the Polyporaceae demonstrate that Crassisporus is grouped with Haploporus but forms a monophyletic lineage. In addition, four new species of Crassisporus, C. imbricatus, C. leucoporus, C. macroporus, and C. microsporus are described.