Abstract
During our fungal forays in freshwater streams of Thailand and China, two new taxa belonging to the family Tubeufiaceae were isolated from decaying submerged wood samples. A new genus Neotubeufia is introduced to accommodate a new species, N. krabiensis, which is comparable to Tubeufia in the features of ascomata, asci and ascospores, but found distinct with dark ascomata, cylindrical asci and cylindric-fusiform ascospores. A multigene phylogenetic analysis based on ITS, LSU, TEF1a and RPB2 sequence data indicate that Neotubeufia formed a single clade distant from the Tubeufia clade. A new species, Tubeufia guangxiensis collected from decaying wood in a freshwater habitat in China is confirmed by comparing morphological characters with the type species T. javanica and other Tubeufia taxa together with phylogenetic analysis. Descriptions, illustrations and notes are provided for the new genus and new species.