Morphological studies, as well as comparisons and phylogenetic analyses of sequences of the 45S (= 18S-ITS-28S) nuc rDNA region and the largest subunit of the RNA polymerase II ( rpb 1) gene of two specimens, preliminarily named Isolate 527 and Isolate 530, showed that they are undescribed species in a newly proposed genus of the family Rhizoglomeraceae and in the genus Dominikia in Dominikiaceae (order Glomerales , phylum Glomeromycota ), respectively. Consequently, Isolate 527 was described as Durabilispora carpatica sp. nov . in Durabilispora gen. nov ., and Isolate 530 as Dominikia tatrensis sp. nov . Durabilispora was previously identified as an undescribed genus informally named “gen21” by other researchers. Both new species produced glomoid glomerospores in glomerocarps, which were extracted from trap cultures inoculated with mixtures of rhizosphere soils and root fragments of meadow plants from the Tatra Mountains, southern Poland. The morphological identity of Du. carpatica to the previously found Isolate 299, which was not provided with genetic data, indicated that Du. carpatica also inhabited dunes of the Baltic Sea in northern Poland.

Nivicolous myxomycetes are an ecological group of protists associated with melting snowfields in mountainous regions. In this study, we document 11 nivicolous myxomycete species new to Poland, based on 123 herbarium specimens collected over the last 40 years in the Carpathians, one of the largest mountain ranges in Central Europe. This includes six species reported here for the first time from the entire Carpathians: Badhamia alpina, Lamproderma cristatum, L. cucumer, L. piriforme, L. pseudomaculatum, and Polyschismium granuliferum. Our findings highlight the importance of further research on nivicolous myxomycetes in the Carpathian Mountain Range.

This article is the 19th contribution to the fungal diversity notes series, in which 106 taxa distributed in 3 phyla, 11 classes, 35 orders, and 64 families are treated. Taxa described in the present study include a new family, 5 new genera, 69 new species, 3 new combinations, 25 new host, habitat, and geographical records, a new name, a new collection, as well as reinstating a previously suppressed genus. The newly established family is Parasporidesmiaceae and the five new genera described herein are Dematiodidymosporum, Neoacrogenospora, Parasporidesmium, Speluncomyces, and Uniomyces. The 69 new species are Acrocalymma triseptatum, Agaricus darjeelingensis, Annellophorella aquatica, Anteaglonium menghaiense, Balsamia microspora, Bambusicola dehongensis, Barriopsis menglaense, Benjaminiomyces bergonzoi, Camporesiomyces aquaticus, Camporesiomyces wurfbainiae, Cercospora palmata, Chrysomphalina cantharella, Colletotrichum heteropanacicola, Conioscypha guizhouensis, Conioscypha yadongensis, Cora dalfornoae, Cylindromonium brasiliense, Dematiodidymosporum aquaticum, Distoseptispora dinghuensis, Distoseptispora zunyiensis, Ebollia neocarnea, Eudimeromyces aequatorialis, Eudimeromyces euconni, Funalia indica, Fuscosporella ovalis, Fuscosporella yunnanensis, Halobasidium csapodyae, Halokirschsteiniothelia hunanensis, Hongkongmyces xishuangbannaensis, Inocybe ispartaensis, Laboulbenia neofrancoisiana, Lachnella kunmingensis, Lasmenia thailandica, Leptospora cannabini, Lycoperdon sridharii, Myxospora neomasonii, Natipusilla aquatica, Neoacrogenospora aquatica, Neomassaria sinensis, Neovaginatispora juglandis, Niesslia yunnanensis, Ophiocordyceps aseptatospora, Oxneriaria sheosarensis, Paramicrosphaeropsis vitis, Paramyrothecium strychni, Parapaucispora aquatica, Parasporidesmium aquaticum, Parmelia neosaxatilis, Periconia bambusicola, Periconia neohongheensis, Peroneutypa thailandica, Polyozellus albus, Porina magnoliae, Porostereum subspadiceum, Pseudosperma subvolvatum, Pseudothyridariella caseariae, Rhexocercosporidium ferulae, Russula rubroglutinata, Septoriella iranica, Seriascoma asexuale, Sesquicillium flavum, Sirastachys zhongkaiensis, Speluncomyces lunatus, Sporidesmiella yunnanensis, Striaticonidium xishuangbannaensis, Trametopsis indica, Tulostoma hyderabadensis, Uniomyces hakkeijimanus, and Virgaria guizhouensis. The three new combinations are Lycoperdon alpinum, Lycoperdon lloydii, and Lycoperdon macrogemmae. The 25 new records comprise Acremonium sclerotigenum, Agroathelia rolfsii, Alfaria terrestris, Aspergillus cejpii, Colletotrichum brevisporum, Coriolopsis brunneoleuca, Coriolopsis hainanensis, Cytospora tamaricicola, Fomitopsis malicola, Fulvifomes fastuosus, Fulvifomes thailandicus, Funalia cystidiata, Funalia subgallica, Longididymella vitalbae, Lopharia mirabilis, Metarhizium viridulum, Neopestalotiopsis haikouensis, Occultibambusa aquatica, Phaeoacremonium scolyti, Phaeocytostroma virdimurae, Puccinia mysuruensis, Rhizopus stolonifer, Serpula similis, Trametes ellipsospora, and Vamsapriya shiwandashanensis. In addition, the new name is Irpiciporus pseudoxuchilensis, and the new collection is Aspergillus sydowii. The previously suppressed genus Eudimeromyces has been taxonomically reinstated.

Myxomycetes are a unique branch of life, recognisable by sporophores showing a fungus-like dispersal biology. These structures bear nearly all diagnostic characters for species identification and develop by rapid transformation of plasmodia. During this short period of time, external factors can significantly influence the formation of morphological characters. Therefore, the description of a new species must be carried out with utmost care. Over the last 50 years, approximately 10-15 new species of myxomycetes have been described per year and only some of the latest publications underpin this with molecular data. In this paper, we discuss a set of recommendations for the description of myxomycete species new to science, striving for the following goals: (i) to minimise the number of erroneous descriptions of the species, whose names later have to be put into synonymy; (ii) to make all respective data easily accessible for the scientific community; and (iii) to comply with existing rules of nomenclature. We recommend (1) whenever possible not to describe a new taxon from a single specimen; however, an exception could be made only if supported by molecular data and by unique morphological characters which are unlikely to fall in the range of infraspecific variation of related species; (2) preparing detailed descriptions, including data on developmental stages, microhabitats, ecology, phenology and associated species; (3) providing at least two independent diagnostic characters that tell the new species apart from all others; (4) obtaining a molecular barcode and, whenever possible, providing proof for reproductive isolation of the new species from related taxa; and (5) depositing type specimens in public herbaria. To comply with nomenclatural rules, (6) the new name must be registered in a recognised repository, (7) all published names should be checked for usability before proposing a new name and (8) a unique name should be chosen, preferably highlighting a distinct character of the new species.

The fundamental value of universal nomenclatural systems in biology is that they enable unambiguous scientific communication. However, the stability of these systems is threatened by recent discussions asking for a fairer nomenclature, raising the possibility of bulk revision processes for "inappropriate" names. It is evident that such proposals come from very deep feelings, but we show how they can irreparably damage the foundation of biological communication and, in turn, the sciences that depend on it. There are four essential consequences of objective codes of nomenclature: universality, stability, neutrality, and transculturality. These codes provide fair and impartial guides to the principles governing biological nomenclature and allow unambiguous universal communication in biology. Accordingly, no subjective proposals should be allowed to undermine them.

Brilliant colors in nature arise from the interference of light with periodic nanostructures resulting in structural color. While such biological photonic structures have long attracted interest in insects and plants, they are little known in other groups of organisms. Unexpected in the kingdom of Amoebozoa, which assembles unicellular organisms, structural colors were observed in myxomycetes, an evolutionary group of amoebae forming macroscopic, fungal-like structures. Previous work related the sparkling appearance of Diachea leucopodia to thin film interference. Using optical and ultrastructural characterization, we here investigated the occurrence of structural color across 22 species representing two major evolutionary clades of myxomycetes including 14 genera. All investigated species showed thin film interference at the peridium, producing colors with hues distributed throughout the visible range that were altered by pigmentary absorption. A white reflective layer of densely packed calcium-rich shells is observed in a compound peridium in Metatrichia vesparium , whose formation and function are still unknown. These results raise interesting questions on the biological relevance of thin film structural colors in myxomycetes, suggesting they may be a by-product of their reproductive cycle.

The Tatra Mts are the highest mountain range in the Carpathians and are an important biodiversity region for many organisms. Plants, animals, and fungi are better studied in this region, while myxomycetes still remain understudied. This study presents the most up-to-date checklist of myxomycetes in the Polish Tatra Mts. The list is based on the published literature data and new records from the years 2000-2019. Overall, 85 species are reported, four are new to Poland ( Arcyria cf. helvetica , Cribraria macrospora , Fuligo cf. licentii , and Nannengaella cf. mellea ), and 30 taxa (species or varieties) are reported for the first time from the study area.

Recent molecular investigations indicate that different species of the myxomycete genus Reticularia belong to different families. In 2019, the species R. olivacea was transferred to the family Cribrariaceae with the re-erection of the generic name Licaethalium. However, the name Enteridium, previously considered a synonym of Reticularia, has a priority over Licaethalium. On this basis, but also relying on morphological considerations, we propose to treat the species of Cribrariaceae forming aethalia within the genus Enteridium and suggest recognizing two species within this genus: E. olivaceum and E. simulans.

The Global Consortium for the Classification of Fungi and fungus-like taxa is an international initiative of more than 550 mycologists to develop an electronic structure for the classification of these organisms. The members of the Consortium originate from 55 countries/regions worldwide, from a wide range of disciplines, and include senior, mid-career and early-career mycologists and plant pathologists. The Consortium will publish a biannual update of the Outline of Fungi and fungus-like taxa, to act as an international scheme for other scientists. Notes on all newly published taxa at or above the level of species will be prepared and published online on the Outline of Fungi website (https://www.outlineoffungi.org/), and these will be finally published in the biannual edition of the Outline of Fungi and fungus-like taxa. Comments on recent important taxonomic opinions on controversial topics will be included in the biannual outline. For example, 'to promote a more stable taxonomy in Fusarium given the divergences over its generic delimitation', or 'are there too many genera in the Boletales?' and even more importantly, 'what should be done with the tremendously diverse 'dark fungal taxa?' There are undeniable differences in mycologists' perceptions and opinions regarding species classification as well as the establishment of new species. Given the pluralistic nature of fungal taxonomy and its implications for species concepts and the nature of species, this consortium aims to provide a platform to better refine and stabilise fungal classification, taking into consideration views from different parties. In the future, a confidential voting system will be set up to gauge the opinions of all mycologists in the Consortium on important topics. The results of such surveys will be presented to the International Commission on the Taxonomy of Fungi (ICTF) and the Nomenclature Committee for Fungi (NCF) with opinions and percentages of votes for and against. Criticisms based on scientific evidence with regards to nomenclature, classifications, and taxonomic concepts will be welcomed, and any recommendations on specific taxonomic issues will also be encouraged; however, we will encourage professionally and ethically responsible criticisms of others' work. This biannual ongoing project will provide an outlet for advances in various topics of fungal classification, nomenclature, and taxonomic concepts and lead to a community-agreed classification scheme for the fungi and fungus-like taxa. Interested parties should contact the lead author if they would like to be involved in future outlines.

Revision of available syntypes of Dianema harveyi Rex revealed that two of them represent another species, Prototrichia metallica. In order to clarify the species interpretation, Dianema harveyi is typified, described based on original material, and illustrated.

Clathrus archeri is one of several alien species for the Polish mycobiota. It has been brought over to Europe from Australia and New Zealand and was recorded for the first time in Poland in the 70s of the 20th century. Since then, records of this species have steadily increased, with their majority located in the southern part of Poland. This paper presents a new locality of C. archeri in the Karkonosze National Park, in ATPOL square AE89 (50°46′04.4″N, 15°42′10.6″E), elevation: 1100 m a.s.l. (Fig. 1). To date, this is the highest known locality of C. archeri in the Karkonosze National Park and the Sudetes.

Type specimens of four species of Lepidoderma (Myxomycetes, Amoebozoa)-L. crassipes, L. neoperforatum, L. perforatum, and L. stipitatum-have been studied using an integrative approach including application of traditional taxonomy methods, i.e., morphological study under stereoscopic and compound microscopes, detailed analysis of micromorphological characters using scanning electron microscopy, and molecular analysis by way of Sanger sequencing of molecular markers (nuc 18S rDNA and elongation factor 1-alpha gene, EF1A). Results of the study revealed that L. crassipes is conspecific with L. tigrinum, L. stipitatum is a malformed specimen of Diderma floriforme, whereas L. perforatum and L. neoperforatum represent two well-defined morphologically and genetically separate species. Phylogeny of Physarales shows the polyphyletic character of the genus Lepidoderma. The type species of Lepidoderma clusters together with Diderma, whereas other representatives of this genus form a monophyletic, well-supported clade. The species from this clade are proposed to belong to the genus Polyschismium described by A. Corda in 1842 that is resurrected and emended here. Nine species of Lepidoderma are transferred to Polyschismium. A new key to Didymiaceae including Polyschismium is provided.

Donald T. Kowalski’s herbarium collection gathered in 1960s is among the most important historical documentation of nivicolous myxomycete diversity in North America. A revision of speciose genus Lamproderma from this collection deposited in UC was undertaken. Based on examination of 95 specimens that were originally classified by Kowalski into 13 species, 25 species have been recognized. The identity of seven species: L. arcyrionema, L. biasperosporum, L. columbinum, L. disseminatum, L. echinosporum, L. maculatum, and L. scintillans was confirmed and all specimens represented the species as originally determined by Kowalski. Remaining 18 species were either differently interpreted or not distinguished by Kowalski. The most interesting of them is a single collection of Diacheopsis sp. that most likely belongs to an undescribed species. Attempts to obtain molecular barcode reference sequences from Kowalski’s specimens failed, likely due to the degradation of DNA induced by chemical treatment of collections in the past, thus this material remains available only for morphological comparisons. Results of the present revision contribute to more adequate estimation of diversity of Lamproderma species in the USA revealing a much higher number of species than originally reported. More generally, these results emphasize a need of revisions of old collections what is particularly important in the genera like Lamproderma where taxonomic changes proposed during last decades made older published records unequivocal or difficult to interpret.

Nivicolous myxomycetes are an ecological group of fungus-like microorganisms associ-ated with long-lasting snow cover. Their global diversity and biogeography remains poorly investi-gated and understood. In this work, we focused on a recently discovered population of a nivicolous species Didymium nivicola from an isolated locality in Tenerife, Canary Islands. As revealed in previous studies, D. nivicola occurs in the Northern Hemisphere (Europe, North America, Asia), where it is genetically uniform, and in the Southern Hemisphere (South America), where it is ge-netically diverse. Based on sequence data from two DNA regions (SSU and EF1A) we revealed that the geographically isolated specimens from Tenerife form a well-defined, previously undetected D. nivicola lineage. This lineage is distinct from a genetically uniform metapopulation of D. nivi-cola which extends over three continents of the Northern Hemisphere, what indicates that this population has a different biogeographical history than the metapopulation from the rest of the Northern Hemisphere. Reconstruction of the ancestral area (S-DIVA and BBM) indicated close af-finity of the Canarian population of D. nivicola to the South American population. This assumption has been supported by morphological characters. Accordingly, we hypothesise that the Canarian population of D. nivicola may originate from South America. Whether the new lineage is specific for the islands or may also occur in the continental Africa could not be verified because no popula-tions have been recorded from this area so far.

A new nivicolous myxomycete is described as a result of a comprehensive study of Didymium nivicola collections from the entire range of its occurrence. Statistical analysis of 12 morphological characters, phylogenetic analyses of nuc 18S rDNA and elongation factor 1-alpha gene (EF1A), and a delimitation method (automatic barcode gap diversity) have been applied to corroborate the identity of the new species. A preliminary morphological analysis of D. nivicola revealed high variability of South American populations where four types of spore ornamentation were noted. However, results of molecular study and statistical analysis of morphological characters did not support recognition of these four forms but the distinction of two morphotypes. Consequently, two species have been recognized: D. nivicola and the newly proposed D. pseudonivicola. The new species can be distinguished from D. nivicola by distinctly larger and mostly plasmodiocarpic sporophores, which are scattered to gregarious, paler spores, and by the paler, more delicate and more elastic capillitium. Spore ornamentation of D. pseudonivicola is uniform and can be described as distinctly spiny (pilate under scanning electron microscope [SEM]), whereas those of D. nivicola is more variable, where spines (pilae under SEM) are delicate, distinct, or conspicuous. Additionally, whereas D. nivicola is a species distributed worldwide, D. pseudonivicola occurs only in the austral Andes of Argentina and Chile.

Herbarium collections provide an essential basis for a wide array of biological research and, with development of DNA-based methods, they have become an invaluable material for genetic analyses. Yet, the use of such material is hindered by technical limitations related to DNA degradation and to quantity of biological material. The latter is inherent for some biological groups, as best exemplified by myxomycetes which form minute sporophores. It is estimated that ca. two-thirds of myxomycete taxa are represented by extremely scanty material. As DNA isolation methods applied so far in myxomycete studies require destructive sampling of many sporophores, a large part of described diversity of the group remains unavailable for phylogenetic studies or barcoding. Here, we tested several procedures of DNA isolation and amplification to seek for an efficient and possibly non-destructive method of sampling. Tests were based on herbarium specimens of 19 species representing different taxonomic orders. We assayed several variants of isolation based on silica gel membrane columns, and a newly designed procedure using highly reduced amount of biological material (small portion of spores), based on fine disruption of spores and direct PCR. While the most frequently used column-based method led to PCR success in 89.5% of samples when a large amount of material was used, its performance dropped to 52% when based on single sporophores. Single sporophores provided amplicons in 89.5% of samples when using a kit dedicated to low-amount DNA samples. Our new procedure appeared the most effective (94.7%) while it used only a small fraction of spores, being nearly non-destructive; it was also the most cost-effective. We thus demonstrate that combination of adequate handling of spore micro-disruption coupled with application of direct PCR can be an efficient way to circumvent technical limitations for genetic studies in myxomycetes and thus can substantially improve taxon sampling for phylogeny and barcoding. Additionally, this approach gives a unique possibility to apply both molecular and morphological assays to the same structure (sporophore), which then can be further stored as documentation.

Soil protists play a crucial role in terrestrial ecosystems and often show immense taxonomic diversity. However, for many groups, distribution patterns remain largely unknown. We investigated range-wide intraspecific diversity of a specialized airborne protist (Didymium nivicola Meyl.) that occupies a narrow ecological niche associated with long-lasting snow cover. We sampled 122 collections covering all areas where the species was recorded worldwide. We obtained 105 and 41 sequences of small ribosomal subunit rDNA (SSU) and elongation factor 1-alpha (EF1A), respectively. While the species is very diverse in the austral Andes, Southern Hemisphere (SH; 17 SSU ribotypes and 12 EF1A genotypes identified), its populations are genetically uniform across three continents of the Northern Hemisphere (NH; single ribotype, single genotype). Our results indicate the austral Andes as a possible diversification centre for D. nivicola where populations seem to reproduce sexually. Two main parts of the range display highly contrasting genetic patterns, thus biogeographical history and dynamics. Current distribution of D. nivicola in the NH is likely a result of a dispersal event from the SH and subsequent long-distance dispersal (LDD) that might be associated with a shift to asexual mode of reproduction.

Nivicolous myxomycetes are a group of amoebozoan protists dependent on long-lasting snow cover worldwide. Recent fine-scale analysis of species diversity from the austral Andes revealed high intraspecific variability of most taxa, suggesting independent evolutionary processes and significant differences in species compositions between the Northern (NH) and Southern (SH) Hemispheres. The present study is the second part of this analysis based on representatives of Trichiales. A total of 173 South American collections were studied based on morphological and molecular data, and 15 taxa have been identified. Two of them,Hemitrichia crassifilaandPerichaena patagonica, are proposed as new species confirmed by a phylogeny of Trichiales. However, their affinity to the genera in which they are proposed are not confirmed due to polyphyletic character of all genera of Trichiales. Four species,Dianema subretisporum, Trichia contortavar.karstenii, T. nivicola, andT. sordida, are reported for the first time from the Southern Hemisphere. One species,T. alpina, is new for Argentina. Additionally, we provide the first record ofPerichaena megasporafrom Chile. Specimen frequency and species diversity of Trichiales found at nivicolous localities in the austral Andes are unexpectedly high, exceeding those of Stemonitidales, the most numerous group in the Northern Hemisphere, where Trichiales play a marginal role. By contrast, Trichiales appear the main component of nivicolous assemblages in the Andes. Results of the present work, together with the earlier analysis of Stemonitidales, indicate that the Andes constitute an exceptionally important evolutionary hot spot for nivicolous myxomycetes characterized by an outstanding species diversity.

Trichia sordida Johannesen represents the ecological guild of nivicolous myxomycetes, which occurs in mountainous areas at the edge of melting winter snow cover. It is not very common in the Northern Hemisphere and has never been reported from Poland. In the spring of 2020, two specimens of it were found in the Tatra Mts, in spruce forest close to the Polana Upłaz meadow on the Ciemniak massif (49°15′05.0″N, 19°52′46.4″E; Figs 1, 2). Together with the newly reported species the list of nivicolous myxomycetes reported from the Tatra Mts numbers eleven species. Trichia sordida is also reported for the first time for the entire Carpathian range.