Using the basic GenBank local alignment search tool program (BLAST) to identify fungi collected in a recently protected beech forest at Montricher (Switzerland), the number of ITS sequences associated to the wrong taxon name appears to be around 30%, even higher than previously estimated. Such results rely on the in-depth re-examination of BLAST results for the most interesting species that were collected, viz. first records for Switzerland, rare or patrimonial species and problematic species (when BLAST top scores were equally high for different species), all belonging to Agaricomycotina. This paper dissects for the first time a number of sequence-based identifications, thereby showing in every detail—particularly to the user community of taxonomic information—why sequence-based identification in the context of a fungal inventory can easily go wrong. Our first conclusion is that in-depth examination of BLAST results is too time consuming to be considered as a routine approach for future inventories: we spent two months on verification of approx. 20 identifications. Apart from the fact that poor taxon coverage in public depositories remains the principal impediment for successful species identification, it can be deplored that even very recent fungal sequence deposits in GenBank involve an uncomfortably high number of misidentifications or errors with associated metadata. While checking the original publications associated with top score sequences for the few examples that were here re-examined, a positive consequence is that we uncovered over 80 type sequences that were not annotated as types in GenBank. Advantages and pitfalls of sequence-based identification are discussed, particularly in the light of undertaking fungal inventories. Recommendations are made to avoid or reduce some of the major problems with sequence-based identification. Nevertheless, the prospects for a more reliable sequence-based identification of fungi remain quite dim, unless authors are ready to check and update the metadata associated with previously deposited sequences in their publications.

In this new series of Fungal Biodiversity Profiles, the authors describe seven new Russulales: five new species of Lactarius subg. Russularia and two new Russulas: descriptions and ITS sequences are provided for L. aurantiobrunneus X.H. Wang, sp. nov., L. collybioides X.H. Wang, sp. nov., L. exilis X.H. Wang, sp. nov., L. flaviaquosus X.H. Wang, sp. nov., and L. resinosus X.H. Wang, sp. nov., from China, as well as for Russula clavatohyphata R.P. Bhatt, A. Ghosh, Buyck & K. Das, sp. nov., from Indian Himalaya, and R. capillaris Buyck, sp. nov., from Madagascar. In addition, first ITS sequences are provided for several specimens of the North American R. burlinghamiae Singer. Two bamboo-inhabiting species are described from Asia: Serpula dendrocalami C.L. Zhao, sp. nov., in Boletales, is described from China, while Hymenochaete sharmae Hembrom, K. Das & A. Parihar, sp. nov., in Hymenochaetales, is described from India. Finally, in Agaricales, Laccaria indohimalayana K. Das, I. Bera & Vizzini, sp. nov., is described from Indian Himalaya.

In this new series of Fungal Biodiversity Profiles, the authors describe ten species new to science, nine basidiomycetes and one ascomycete, using both morphological and molecular data. Descriptions are provided for Hydnum berkeleyanum sp. nov. (Cantharellales), for Lactarius ambiguus, L. furfuraceus, L. orientaliquietus, L. subhirtipes, Russula blennia, R. pseudociliata (Russulales), Marasmius pseudohypochrysoides, Radulomyces paumanokensis (Agaricales) and Urnula himalayana (Pezizales).

In this new series of Fungal Biodiversity Profiles, the authors describe three new Laboulbeniales (Ascomycota) based on morphology, viz. Corethromyces gibbosus W. Rossi & Santam., sp. nov., C. marshallii W. Rossi & Santam., sp. nov. and Diphymyces torresii W. Rossi & Santam., sp. nov. In Agaricomycotina (Basidiomycota), morphological features and multigene phylogenetic analyses support the description of Cantharellus albidosquamosus Buyck, T. W. Henkel & V. Hofst., sp. nov. (Cantharellales), while morphology and analyses of ITS sequence data support the description of Gomphidius pseudoglutinosus K. Das, Hembrom, A. Parihar & Vizzini, sp. nov. (Boletales) and of two Gomphales, Hymenochaete boddingii Hembrom, A. Parihar, K. Das & A. Ghosh, sp. nov. and Ramaria thindii K. Das, Hembrom, A. Parihar & A. Ghosh, sp. nov. In Russulales, recently published multigene phylogenetic analyses support the description of Russula antsikana Buyck & Randrianjohany, sp. nov. from Madagascar, and a barcode ITS sequence is newly provided for the holotype. In addition, a detailed description is given for the type of the West-African Russula liberiensis Sing., likely its closest relative. Still in genus Russula, a new multigene analysis supports the description of subsect. Castanopsidum Buyck & X.H. Wang, subsect. nov. for a species assemblage in the Russula crown clade that seems to have its main distribution in Asia.

The ability of fungi isolated from nails of patients suffering from onychomycosis to induce de novo production of bioactive compounds in co-culture was examined. Comparison between the metabolite profiles produced by Sarocladium strictum, by Fusarium oxysporum, and by these two species in co-culture revealed de novo induction of fusaric acid based on HRMS. Structure confirmation of this toxin, using sensitive microflow NMR, required only three 9-cm Petri dishes of fungal culture. A targeted metabolomics study based on UHPLC-HRMS confirmed that the production of fusaric acid was strain-dependent. Furthermore, the detected toxin levels suggested that onychomycosis-associated fungal strains of the F. oxysporum and F. fujikuroi species complexes are much more frequently producing fusaric acid, and in higher amount, than strains of the F. solani species complex. Fusarium strains producing no significant amounts of this compound in pure culture, were shown to de novo produce that compound when grown in co-culture. The role of fusaric acid in fungal virulence and defense is discussed.

This new series of Fungal Biodiversity Profiles presents ten new taxa in the genus Russula, including subgenus Crassotunicata subg. nov. In subg. Malodora, sect Edules sect. nov. is described for a number of African species and a first detailed description is given for the type species, while R. pseudocompacta sp. nov. and R. compactoides sp.nov. are described in the new section Pseudocompactae sect. nov. of the same subgenus; in subg. Compactae the new sect. Polyphyllae is described, in subg. Russula, R. kewzingensis sp. nov. is described in subsect. Roseinae, as well as the new section Flavisiccantes, and the new subsect. Tricholomopsidae.