Abstract
Microdochium has been reported worldwide as a plant pathogen, endophyte, or saprotroph. This study utilized four genetic loci (ITS, LSU, rpb2, and tub2) along with morphological characteristics, employing maximum likelihood and Bayesian inference analyses to identify and establish the taxonomic status of four new species from two host plants (Bambusaceae sp. and Phragmites australis) in Hainan Province, China. We propose four new species, Microdochium australiana sp. nov., M. baishamenense sp. nov., M. bambusina sp. nov., and M. bambusarum sp. nov. We provide detailed descriptions and micrographs of these species and compare them with other Microdochium species.