Aquatic hyphomycetes are a diverse, polyphyletic group of asexually reproducing fungi involved in the decomposition of litter in freshwater ecosystems. Curvularia eragrostidis, C. verruculosa and Phragmocephala atra were identified from submerged wood collected from freshwater streams in Yunnan Province, Southwestern China. They were characterised based on morphology and LSU, ITS and SSU sequence data. Phylogenetic analysis of LSU sequences placed the isolates within the order Pleosporales. Curvularia eragrostidis and C. verruculosa are reported from freshwater habitats for the first time. An epitype is designated for Curvularia verruculosa. This is the first phylogenetic placement of the genus Phragmocephala in the family Melanommataceae in Dothideomycetes, providing new DNA sequence data. A new species, Phragmocephala garethjonesii is introduced based on DNA sequence data and morphology. Descriptions and illustrations are provided for the species with notes on their taxonomy and phylogeny.