Eight hyphomycetes were collected as part of an investigation into the diversity of hyphomycetous fungi in China. Based on morphology and multi-loci (LSU, ITS, tef1α, and rpb2) phylogenetic analyses, five new taxa, including a new Aquapteridospora species A. hyalina and four novel Distoseptispora species, viz D. aquisubtropica, D. septata, D. tropica, and D. wuzhishanensis were introduced in Distoseptisporales (Sordariomycetes). Two new habitat records, viz Distoseptispora pachyconidia and D. xishuangbannaensis were firstly reported. Also provided in this study are detailed descriptions of eight new collections and a revised phylogenetic tree for the Distoseptisporales.

An investigation of freshwater fungi in Thailand resulted in the collection of one new monotypic genus, Neoxylomyces, and a novel species each in Camposporium, Brunneofusispora, Rattania, Neoxylomyces, and Phaeoacremonium. Camposporium dulciaquae resembles C. septatum in conidial morphology and number of septa but differs in conidial sizes. Brunneofusispora hyalina is similar to B. sinensis in conidiogenesis and conidial shape but differs in the sizes of conidiomata and conidiogenous cells. Rattania aquatica is the second species in Rattania, while Phaeoacremonium thailandense is the third species recorded from freshwater habitats. A new genus, Neoxylomyces, typified by N. multiseptatus, is similar to Xylomyces giganteus, but differs in the number of septa, chlamydospore measurements, and absence of a mucilaginous coating around the chlamydospores. These novel taxa form an independent lineage distinct from other species based on multi-loci phylogenetic analyses. Descriptions, illustrations, and notes are provided for each taxon. These new freshwater ascomycetes add to the increasing number of fungi known from Thailand and it is now evident that there are numerous novel taxa awaiting to be described as new freshwater habitats are explored. An update of newly discovered taxa in the widely studied freshwater habitats of Thailand over the last five years is also provided.

China and Thailand are rich in fungal diversity with abundant freshwater resources that are favorable for numerous fungal encounters. Resulting from this, the majority of the Dictyosporiaceae species reported were from these two countries. During the investigation on the diversity of lignicolous freshwater fungi in the Greater Mekong Subregion, eleven collections of cheirosporous species on submerged wood were collected from lentic and lotic habitats in China and Thailand. Phylogenetic analysis that combined nuclear small-subunit ribosomal RNA (SSU), internal transcribed spacer region (ITS), nuclear large subunit ribosomal RNA (LSU) and translation elongation factor 1α (tef 1-α) loci revealed six new species: Dictyocheirospora chiangmaiensis, D. multiappendiculata, D. suae, Digitodesmium aquaticum, Vikalpa grandispora and V. sphaerica. In addition, four known species were also identified and reported based on morphological and phylogenetic evidence. The detailed descriptions and illustrations of these taxa are provided with an updated phylogenetic tree of Dictyosporiaceae.

Three helicosporous hyphomycete collections representing two species were obtained from rotting wood found in freshwater and terrestrial habitats in the Guizhou and Guangxi Provinces, China. A new genus Pseudotubeufia (Tubeufiaceae, Tubeufiales), comprising Ps. hyalospora sp. nov. and Ps. laxispora sp. nov., was introduced with morphological characteristic and molecular data. In addition, the molecular evidence showed that Helicomyces sp. (G.M. 2020-09-19.1), H. roseus (CBS: 102.76), and the new genus Pseudotubeufia clustered together with high support based on a multi-gene (LSU, ITS, tef1α, and rpb2) phylogenetic analysis. Detailed descriptions, illustrations, and notes of the three new collections are provided.

During the investigation of lignicolous freshwater fungi in the Tibetan Plateau habitat, fifteen collections were isolated from submerged decaying wood. Fungal characteristics are commonly found as punctiform or powdery colonies with dark pigmented and muriform conidia. Multigene phylogenetic analyses of combined ITS, LSU, SSU and TEF DNA sequences showed that they belong to three families in Pleosporales. Among them, Paramonodictys dispersa, Pleopunctum megalosporum, Pl. multicellularum and Pl. rotundatum are established as new species. Paradictyoarthrinium hydei, Pleopunctum ellipsoideum and Pl. pseudoellipsoideum are reported as new records on the freshwater habitats in Tibetan Plateau, China. The morphological descriptions and illustrations of the new collections are provided.