Bálint Dima

The largest type study of Agaricales species to date: bringing identification and nomenclature of Phlegmacium (Cortinarius) into the DNA era

Cortinarius is a species-rich and morphologically challenging genus with a cosmopolitan distribution. Many names have not been used consistently and in some instances the same species has been described two or more times under separate names. This study focuses on subg. Phlegmacium as traditionally defined and includes species from boreal and temperate areas of the northern hemisphere. Our goals for this project were to: i) study type material to determine which species already have been described; ii) stabilize the use of Friesian and other older names by choosing a neo- or epitype; iii) describe new species that were discovered during the process of studying specimens; and iv) establish an accurate ITS barcoding database for Phlegmacium species. A total of 236 types representing 154 species were studied. Of these 114 species are described only once whereas 40 species had one ore more synonyms. Of the names studied only 61 were currently represented in GenBank. Neotypes are proposed for 21 species, and epitypes are designated for three species. In addition, 20 new species are described and six new combinations made. As a consequence ITS barcodes for 175 Cortinarius species are released.

Determining threshold values for barcoding fungi: lessons from Cortinarius (Basidiomycota), a highly diverse and widespread ectomycorrhizal genus

Different distance-based threshold selection approaches were used to assess and compare use of the internal transcribed spacer (ITS) region to distinguish among 901 Cortinarius species represented by >3000 collections. Sources of error associated with genetic markers and selection approaches were explored and evaluated using MOTUs from genus and lineage based-alignments. Our study indicates that 1%-2% more species can be distinguished by using the full-length ITS barcode as compared to either the ITS1 or ITS2 regions alone. Optimal threshold values for different picking approaches and genetic marker lengths inferred from a subset of species containing major lineages ranged from 97.0% to 99.5% sequence similarity using clustering optimization and UNITE SH, and from 1% to 2% sequence dissimilarity with CROP. Errors for the optimal cutoff ranged from 0% to 70%, and these can be reduced to a maximum of 22% when excluding species lacking a barcode gap. A threshold value of 99% is suitable for distinguishing species in the majority of lineages in the genus using the entire ITS region but only 90% of the species could be identified using just the ITS1 or ITS2 region. Prior identification of species, lacking barcode gaps and their subsequent separate analyses, maximized the accuracy of threshold approaches.

Two new species of Cortinarius, subgenus Telamonia, sections Colymbadini and Uracei, from Europe

Two new Cortinarius species are described from European Quercus forests and one new combination is made based on molecular and morphological data. Cortinarius uraceomajalis is a vernal species currently only known from Hungary, Bulgaria and Italy, but likely is common throughout central and south-eastern Europe. Cortinarius uraceonemoralis is a widely distributed species in Europe. The new combination Cortinarius nolaneiformis is based on Hydrocybe nolaneiformis Velen. and is a widespread vernal species in Europe. Cortinarius uraceomajalis and C. nolaneiformis are preliminarily placed in sect. Colymbadini, characterized by having a positive (yellow) UV reaction, while C. uraceonemoralis with a UV negative reaction is placed in sect. Uracei. A neotype is selected for C. colymbadinus and C. uraceus to stabilize the nomenclature. Taxonomic novelties: Cortinarius uraceomajalis Dima, Liimat., Niskanen & Bojantchev, Cortinarius uraceonemoralis Niskanen, Liimat., Dima, Kytöv., Bojantchev & H. Lindstr., Cortinarius nolaneiformis (Velen.) Dima, Niskanen & Liimat.

Cortinarius, subgenus Telamonia, section Disjungendi, cryptic species in North America and Europe

Cortinarius disjungendus and morphologically similar species were studied using ITS sequences of nine type collections and 18 specimens in the study group, as well as 13 sequences from public sequence repositories, including sequences of three type specimens. In addition, previously published rpb2 sequences were used to provide the phylogenetic position of species in the subgenus Telamonia. Based on these results, the new section Disjungendi, subgenus Telamonia, is proposed. Six species belong to this section: C. claroplaniusculus, C. disjungendus, C. disjungendulus, C. olididisjungendus, C. orasericeus, and C. piceidisjungendus. Of these, C. disjungendus, C. disjungendulus, and C. claroplaniusculus are to date only known from Europe, whereas the others occur both in North America and Europe. Based on ITS sequences, three of the six species had taxonomic synonyms: C. claroplaniusculus (synonym C. hymenoluctus and C. planodepressus), C. disjungendus (synonyms C. remauxii, C. conicosordescens, and C. solivagus), and C. orasericeus (synonym C. brunneofulvus f. myrtillophilus). This study demonstrates how difficult it can be to identify species only on the basis of morphology, and emphasizes the importance of molecular studies of type and of other specimens, particularly in groups with cryptic taxa.

Cortinarius section Bicolores and section Saturnini (Basidiomycota, Agaricales), a morphogenetic overview of European and North American species

Cortinarius is the largest genus of ectomycorrhizal fungi worldwide. Recent molecular studies have shown high levels of morphological homoplasy within the genus. Importantly, DNA phylogenies can reveal characteristics that have been either over- or underemphasized in taxonomic studies. Here we sequenced and phylogenetically analysed a large set of pan-European and North American collections taxonomically studied and placed in Cortinarius sect. Bicolores and sect. Saturnini, according to traditional morpho-anatomical criteria. Our goal was to circumscribe the evolutionary boundaries of the two sections, to stabilize both the limits and nomenclature of relevant species, and to identify described taxa which, according to our current understanding, belong to other lineages. Our analysis resolves two clades: /Bicolores, including 12 species, one of which is new to science, and /Saturnini, including 6 species. Fifteen binomials, traditionally treated in these two sections based on morphology, do not belong to the above two phylogenetic clades. Instead, six of these latter are clearly placed in other clades that represent sect. Bovini, sect. Sciophylli, sect. Duracini and sect. Brunneotincti. The presence or absence of blue pigments and the detection of specific odours emerge as clearly misleading taxonomic features, but more surprisingly, spore size and ecology can be misleading as well. A total of 63 type specimens were sequenced, 4 neotypes and 2 epitypes are proposed here, and 1 new combination is made.

Typification of Friesian names in Cortinarius sections Anomali, Spilomei, and Bolares, and description of two new species from northern Europe

Seven commonly used Friesian names of Cortinarius sect. Anomali, Spilomei, and Bolares are discussed. Neotypes for C. anomalus, C. spilomeus, and C. bolaris, as well as epitypes for C. albocyaneus, C. caninus, and C. tabularis are proposed. The distinction of these six species is supported by both morphological and rDNA internal transcribed spacer (ITS) data, whereas C. azureus, as currently typified, is considered as a synonym of C. anomalus, but could also be considered as nomen dubium. Barcodes (ITS) and morphological descriptions based on materials from a broad geographical area in Europe are provided for each species. Furthermore, two new species, C. jonimitchelliae and C. pastoralis, from northern Europe are described. The latter is proposed to accommodate C. anomalus subsp. campestris, which has been described from treeless habitats with Helianthemum. Our study reveals that the subsp. campestris is not an intraspecific variety of C. anomalus, but an own species close to C. caninus, and has a much wider distribution and host range than earlier thought. An identification key for the species/sections included here is provided.

Psathyloma, a new genus in Hymenogastraceae described from New Zealand

A new genus Psathyloma is described based on collections of agarics from New Zealand. We describe two new species in the genus, Ps. leucocarpum and Ps. catervatim, both of which have been known and tentatively named for a long time awaiting a formal description. Morphological traits and phylogenetic analyses reveal that Psathyloma forms a strongly supported sister clade to Hebeloma, Naucoria and Hymenogaster. Morphologically Psathyloma resembles Hebeloma from which it differs mainly by producing smooth basidiospores with a germ pore. The geographical range of the genus has been demonstrated to include several regions in the southern hemisphere. A survey of published environmental sequences reveals that Psathyloma spp. were isolated from ectomycorrhizal root tips from Tasmania and Argentina, indicating an ectomycorrhizal association with southern beech.

Cortinarius prodigiosus—a new species of the subgenus Phlegmacium from Central Europe

A new species, Cortinarius prodigiosus, is reported from the Czech Republic and Hungary. This medium-sized Phlegmacium is distinguished by a yellow pileus and lower part of stipe, by greyish-violet lamellae, and by strikingly bicolorous flesh: yellow in most parts of stipe and whitish in pileus. On the basis of its morphological and molecular characters (ITS rDNA and LSU D1/D2 domain), this novel taxon can be assigned to the Splendentes group of the section Calochroi; it occurs in thermophilous oak forests on calcareous bedrock.

New systematic position of Aurantiporus alborubescens (Meruliaceae, Basidiomycota), a threatened old-growth forest polypore

Odoria (Meruliaceae, Basidiomycota) is described as a new genus established for the threatened old-growth forest polypore Phaeolus alborubescens that was previously discussed in Aurantiporus or Tyromyces. It is characterized by the annual pinkish white spongy basidiocarp with strong sweetish smell, turning pale brown when drying, and has a positive reaction with KOH solution, the lack of cystidia, and the monomitic hyphal system with clamped generative hyphae often covered with fine orange crystals. Multigene phylogenetic analyses based on a combined (5.8S–nucLSU–rpb1–rpb2) and a single locus (nrITS) dataset place Odoria in Meruliaceae (Phlebioid clade), close to Crustodontia, Sarcodontia, Luteoporia, and Phlebiporia. Molecular as well as anatomical study of the old type specimen of P. alborubescens is also provided.

Cortinarius stjernegaardii and C. kristinae (Basidiomycota, Agaricales), two new European species with a mainly northern distribution

We describe two new, mainly North European species of basidiomycetous fungi. Cortinarius stjernegaardii belongs to the section Percomes containing several similar species with greenish-yellow, anthraquinonoid pigments and peculiar smells. The species has hitherto been identified as” C. bulbopodius” in the Nordic countries, an epithet which, however, is reduced to a synonym of C. aurilicis. Cortinarius kristinae belongs to the section Calochroi, which includes many morphologically similar species with sharply marginate bulbose stipes and yellow pileus colours. The species are distinguished from related taxa by molecular data (ribosomal ITS region), and typical specimens can be identified by a combination of basidiocarp coloration, stature, microscopy, reactions with KOH, and habitat.