A Phylogenetic and Taxonomic Study on Xylodon (Hymenochaetales): Focusing on Three New Xylodon Species from Southern China.

ABSTRACT

Three wood-inhabiting fungal species, Xylodon laceratus, X. montanus, and X. tropicus spp. nov., were collected from southern China, here proposed as new taxa based on a combination of morphological features and molecular evidence. Xylodon laceratus is characterized by the resupinate basidiomata with grandinioid hymenophore having cracked hymenial surface, and ellipsoid basidiospores; X. montanus is characterized by the annual basidiomata having the hard, brittle hymenophore with cream hymenial surface, and ellipsoid to broadly ellipsoid basidiospores (3.9-5.3 × 3.2-4.3 µm); and X. tropicus is characterized by its grandinioid hymenophore with buff to a pale brown hymenial surface and subglobose basidiospores measuring 2-4.8 × 1.6-4 µm. Sequences of ITS and nLSU rRNA markers of the studied samples were generated, and phylogenetic analyses were performed with maximum likelihood, maximum parsimony, and Bayesian inference methods. The ITS+nLSU analysis of the order Hymenochaetales indicated that the three new species clustered into the family Schizoporaceae, located in genus Xylodon; based on further analysis of ITS dataset, X. laceratus was a sister to X. heterocystidiatus; X. montanus closely grouped with X. subclavatus and X. xinpingensis with high support; while X.tropicus was retrieved as a sister to X. hastifer.