The species is one of the basic units of biological classification. Both species concepts and recognition are essential topics in taxonomic studies and other biological research. In the first part of this review, we briefly discuss the taxonomic history of the class Dothideomycetes. In the second part of the paper, we review four commonly used species concepts, focusing on morphological, ecological, biological and phylogenetic criteria and their applicability in the taxonomy of Dothideomycetes. The application and utility of the four criteria is discussed with examples in the genera Ascochyta, Cercospora and Neofusicoccum. Some problems and challenges of studying Dothideomycetes are analyzed and basic guidelines for classifying species under the above criteria are provided.

In the present study, we report two new asexual fungal species (i.e., Discosia rhododendricola, Neopestalotiopsis rhododendricola (Sporocadaceae) and a new host for a previously described species (i.e., Diaporthe nobilis; Diaporthaceae). All species were isolated from Rhododendron spp. in Kunming, Yunnan Province, China. All taxa are described based on morphology, and phylogenetic relationships were inferred using a multigenic approach (LSU, ITS, RPB2, TEF1 and TUB2). The phylogenetic analyses indicated that D. rhododendronicola sp. nov. is phylogenetically related to D. muscicola, and N. rhododendricola sp. nov is related to N. sonnaratae. Diaporthe nobilis is reported herein as a new host record from Rhododendron sp. for China, and its phylogeny is depicted based on ITS, TEF1 and TUB2 sequence data.

During an investigation of fungal saprobes of Yunnan Province, China, a species in Tetraplosphaeriaceae was collected from decaying stems of Saccharum arundinaceum (Poaceae). The taxon has oblong, dark brown to black, four-columned conidia with mostly three long apical appendages. Phylogenetic analyses of combined LSU, SSU, ITS, β-tubulin and tef1-α sequence data revealed that our collection is a member of Tetraploa and has a close affinity to T. aquatica, T. dashaoensis, and T. nagasakiensis. Based on the morphological comparison and multi-locus phylogeny, we introduce T. cylindrica as a new species. The newly discovered taxon is described, illustrated, and compared to related taxa. A taxonomic insight is presented based on our new data regarding the classification problems of asexual and sexual morphs of Tetraploa. In addition, this is the first report of Tetraploa species that occur on Saccharum arundinaceum. The results of the present study will expand our ecological knowledge of Tetraploa.

Most species of Melanommataceae are saprobic on decayed parts of various plants in tropical and temperate terrestrial habitats. During a survey of microfungi associated with terrestrial plants in Uzbekistan, two melanommataceous taxa were collected from dead branches of Rosa ecae (Rosaceae) and Salvia karelinii (Lamiaceae). This study introduces a new species, Melanocucurbitaria uktampratovii, and provides a new host and sexual morph record for Melanocamarosporioides ugamica, based on morphological observations and multi-gene phylogenetic analyses of concatenated LSU, SSU, ITS, and TEF-1 sequence data. Melanocucurbitaria uktampratovii is the second species described within this genus and differs from the type species of Melanocucurbitaria in having smaller ascomata, smaller asci, smaller ascospores, and a different number of septa. The sexual morph of Melanocamarosporioides ugamica is characterized by globose to ovoid ascomata, cylindrical-clavate asci, ellipsoidal, muriform ascospores with 5–7 transversely septate, and 5–11 vertical septa. Illustrations and descriptions are provided, along with ecological and morphological comparisons of similar species within their respective genera.

Camarosporidiella specimens collected from woody plants in central Italy, eastern Ukraine, and southeastern Russia were identified based on morphology and multi-gene (LSU, SSU, ITS, and TEF) sequence analyses. Camarosporidiella caraganicola on Amorpha fruticosa, C. celtidis on Ulmus pumila, C. elaeagnicola on Cytisus ruthenicus are described with new host records and as new fungal records for Ukraine. Camarosporidiella moricola on Morus nigra is newly reported for Italy, and C. robiniicola on Robinia pseudoacacia is new for Ukraine. Camarosporidiella elaeagnicola on Elaeagnus angustifolia is re-described to facilitate identification. Notes on host distribution of Camarosporidiellaceae are also provided.