In this study, fungal specimens of the family Diatrypaceae were collected from karst areas in Guizhou, Hainan and Yunnan Provinces, China. Morpho-molecular analyses confirmed that these new collections comprise a new genusPseudodiatrype, three new species (Diatrype lancangensis,Diatrypella pseudooregonensisandEutypa cerasi), a new combination (Diatrypella oregonensis), two new records (Allodiatrype thailandicaandDiatrypella vulgaris) from China and two other known species (Neoeutypella baoshanensisandParaeutypella citricola). The new taxa are introduced, based on multi-gene phylogenetic analyses (ITS, β-tubulin), as well as morphological analyses. The new genusPseudodiatrypeis characterised by its wart-like stromata with 5–20 ascomata immersed in one stroma and the endostroma composed of thin black outer and inner layers of large white cells with thin, powdery, yellowish cells. These characteristics separate this genus from two similar generaAllodiatrypeandDiatrype. Based on morphological as well as phylogenetic analyses,Diatrype lancangensisis introduced as a new species ofDiatrype. The stromata ofDiatrype lancangensisare similar to those ofD. subundulataandD. undulate, but the ascospores are larger. Based on phylogenetic analyses,Diatrype oregonensisis transferred to the genusDiatrypellaasDiatrypella oregonensiswhileDiatrypella pseudooregonensisis introduced as a new species ofDiatrypellawith 8 spores in an ascus. In addition, multi-gene phylogenetic analyses show thatEutypa cerasiis closely related toE. lata, but the ascomata and asci ofEutypa cerasiare smaller. The polyphyletic nature of some genera of Diatrypaceae has led to confusion in the classification of the family, thus we discuss whether the number of ascospores per asci can still be used as a basis for classification.

Pleosporales comprise a diverse group of fungi with a global distribution and significant ecological importance. A survey on Pleosporales (in Didymosphaeriaceae, Roussoellaceae and Nigrogranaceae) in Guizhou Province, China, was conducted. Specimens were identified, based on morphological characteristics and phylogenetic analyses using a dataset composed of ITS, LSU, SSU, tef1 and rpb2 loci. Maximum Likelihood (ML) and Bayesian analyses were performed. As a result, three new species (Neokalmusia karka, Nigrograna schinifolium and N. trachycarpus) have been discovered, along with two new records for China (Roussoella neopustulans and R. doimaesalongensis) and a known species (Roussoella pseudohysterioides). Morphologically similar species and phylogenetically close taxa are compared and discussed. This study provides detailed information and descriptions of all newly-identified taxa.

During an investigation of Xylariaceae from 2019 to 2020, isolates representing eight Nemania (Xylariacese) species were collected from Yunnan, Guizhou and Hainan Provinces in China. Morphological and multi-gene phylogenetic analyses, based on combined ITS, α-actin, rpb2 and β-tubulin sequences, confirmed that six of them are new to science, viz. Nemania camelliae, N. changningensis, N. cyclobalanopsina, N. feicuiensis, N. lishuicola and N. rubi; one is a new record (N. caries) for China and one is a known species (N. diffusa). Morphological descriptions and illustrations of all species are detailed. In addition, the characteristics of Nemania are summarised and prevailing contradictions in generic concepts are discussed.

Five taxa that morphologically resemble Astrocystis and Collodiscula were collected on bamboo culms from Guizhou, Hainan and Yunnan provinces in China. Based on morphology and molecular analyses (combined ITS, RPB2, β-tubulin and α-actin genes), these species were identified as Astrocystis cocoes (a new record to China), A. bambusicola, Collodiscula japonica and two new species (A. multiloculata and C. lancangjiangensis). Astrocystis multiloculata can be distinguished from other Astrocystis species by its superficial stromata containing many perithecia and larger ascospores (19–25 × 7–11 μm). Collodiscula lancangjiangensis has larger ascospores (26–36.5 × 5–7.5 μm) than those of the most similar species C. fangjingshanensis (19–25.5 × 4.5–6 μm). It also has larger, 3-septate ascospores than C. japonica (1-septate, 19–26 × 4.5–5.5 μm).

Three arecophila-like fungal samples were collected on dead culms of gramineous plants in China. Morphological studies of our new collections and the herbarium specimen of Arecophila gulubiicola (generic type) were conducted and the morphological affinity of our new collections with Arecophila was confirmed. Maximum likelihood and Bayesian analyses using combined ITS, LSU, rpb2 and β-tubulin data from our collections revealed the phylogeny of Cainiaceae. The monospecific genus Alishanica (type species Al. miscanthi), which had been accepted in Cainiaceae, is revisited and synonymised under Arecophila. Based on morphology and phylogeny, Arecophila australis sp. nov. and A. clypeata sp. nov. are introduced as new species, while A. miscanthi is a new record for China. All the new collections are illustrated and described.

Several micro fungi were gathered from bamboo and palm in Guizhou Province, China. In morphology, these taxa resemble Neomassaria, Roussoella and Oxydothis. Multi-gene phylogenetic analyses based on combined ITS, LSU, SSU, rpb2 and tef1 loci confirmed that two are new geographical records for China, (viz. Roussoella siamensis, Neomassaria fabacearum), while two of them are new to science (viz. Oxydothis fortunei sp. nov. and Roussoella bambusarum sp. nov.). The stromata of Roussoella bambusarum are similar to those of R. thailandica, but its ascospores are larger. In addition, multi-gene phylogenetic analyses show that Oxydothis fortunei is closely related to O. inaequalis, but the J- ascus subapical ring as well as the ascospores of O. inaequalis are smaller. Morphological descriptions and illustrations of all species are provided.