Abstract
The diversity of lignicolous freshwater fungi of the Greater Mekong Subregion are currently being studied. In this paper, 18 fresh collections of Pleurotheciaceae from submerged wood in freshwater are characterized based on morphological characters and analyses of ITS, LSU, SSU and RPB2 sequence data. Six new species of Pleurotheciella (P. aquatica, P. fusiformis, P. guttulata, P. lunata, P. saprophytica, P. submersa), one new Phaeoisaria species (Ph. aquatica) and one new Pleurothecium species (Pl. aquaticum) are introduced based on their distinct morphology and evidence from molecular phylogeny. Pleurotheciella uniseptata, Phaeoisaria clematidis and Pleurothecium pulneyense are also redescribed and phylogenetic relationships assessed herein, these species are the first records for China.