During the ongoing investigation of bambusicolous ascomycetous fungi in Yunnan, China, 24 specimens belonging to the family Roussoellaceae were collected and identified based on morphological features and phylogenetic support. Maximum-likelihood (ML) analyses and Bayesian analyses were generated based on the combined data set of ITS, LSU, tef1, and rpb2 loci. The phylogenetic analyses revealed four novel lineages in Roussoella s. str.; thus, we introduced four new species viz., Roussoella multiloculate sp. nov., R. papillate sp. nov., R. sinensis sp. nov., and R. uniloculata sp. nov. Their morphological characters were compared with the known Roussoella taxa, which lack sequence data in the GenBank. Asexual morphs of R. kunmingensis and R. padinae were recorded from dead bamboo culms in China (from the natural substrates) for the first time. Neoroussoella bambusae, Roussoella japanensis, R. nitidula, R. padinae, R. scabrispora, and R. tuberculate were also reported as the first records from China. All new taxa are described and illustrated in detail. Plates are provided for new reports.
Keywords: bambusicolous ascomycetes; new records; new taxa; phylogeny; taxonomy.