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Orbilia xanthostigma, with golden yellow to yellow-orange apothecia and O. leucostigma, with white to very pale rose-lilaceous apothecia, were described by E.M. Fries over 200 years ago. Each of the two taxa, which are not easy to interpret because type material is lacking, was proposed in the past as lectotype of the genus Orbilia. In the here presented circumscription, which follows the current usage, O. xanthostigma is among the most frequently recorded species of the genus, whereas O. leucostigma appears to be much less common. Both grow gregariously on decorticated hygric gymno- and angiosperm wood or rarely bark and show a worldwide distribution. They are characterised by minute, strongly curved, warted ascospores and a dicranidion-like anamorph. Except for apothecial colour, there are no other notable morphological differences between them, either in the teleomorph (asci, ascospores, paraphyses) or anamorph (conidiophores, conidia). Because of their strong similarities, the two taxa have often been treated as infraspecific variants (subspecies, varieties) of a single species or even as synonyms. In order to overcome the ambiguities associated with the two names, O. delicatula, a name proposed by P.A. Karsten for a collection with golden yellow apothecia, was suggested by B. Spooner as a replacement name for them. The present study reveals unexpectedly high ITS and LSU variation within a morphologically extremely homogeneous group, representing over 16 more or less invariable genotypes whenever more than one sample with a sequence was available. ITS and LSU rDNA data from European (Luxembourg, Germany, Ukraine) and Macaronesian (Tenerife) collections suggest that the two colour variants represent two distinct species with a 16.5% ITS and 3.5% LSU D1–D2 distance, but very low infraspecific variation (0.2% ITS, 0% LSU). A sample with scattered yellow apothecia from Luxembourg on a xeric branch deviates from typical European-Macaronesian O. xanthostigma by 4% (ITS) and 0.7% (LSU). Further available sequences from samples from Asia, New Zealand and North America with mainly yellow apothecia clustered in various other clades that represent further distinct genotypes. In the absence of morphological characteristics, none of these genotypes are given names pending further investigation. Only two of these genotypes are sufficiently distinct to be recognised morphologically: O. aureocrenulata from tropical, Middle and South America, with golden yellow apothecia with a crenulate margin and prominent stipe, and O. xanthoflexa from temperate, northeastern North America with yellow sessile apothecia with a smooth margin and larger, less curved, smooth-walled ascospores.

Sclerococcales encompasses a heterogeneous group of fungi, with most of the species included in the genus Sclerococcum (= Dactylospora). Species of Sclerococcum are characterized by having apothecial ascomata with asci covered by an external hemiamyloid gelatin and a thick euamyloid apical cap, while lacking an inner amyloid wall thickening. Asexual morphs, known for few species, are sporodochial. In this study, we describe Pseudosclerococcum golindoi as a new genus and species sister to Sclerococcum in a multigene phylogeny (nuITS, nuLSU, nuSSU, mtSSU). The fungus produces ascomata similar to those of Sclerococcum, but differs in having cylindrical asci embedded in an overall hemiamyloid gelatin with a fissitunicate dehiscence. Unlike Sclerococcum, Pseudosclerococcum golindoi produces a Chalara-like asexual morph. A possible symbiotic association of P. golindoi with Ascocoryne cylichnium is discussed. The presence of a hemiamyloid gelatin on lateral wall of asci, so far largely overlooked, is reported for some Sclerococcum species. Based on ascal characters and interpretation of the phylogenetic analyses, 14 names assigned to saprotrophic species, previously placed in Dactylospora, are combined in Sclerococcum.

The new species Parakarstenia phyllostachydis was discovered on stems of Phyllostachys heteroclada in Sichuan Province of China and is placed in a new genus within Odontotremataceae in this paper. A multigene analysis of a combined nuclear ITS and LSU rDNA and mtSSU sequence dataset and comparable morphologies suggests the taxonomic affinity of the new taxon in this family. Maximum likelihood and Bayesian inference phylogenetic analyses provide evidence that the fungus is best placed in a distinct genus within this family. The new genus is compared with similar genera of Ostropales and a comprehensive description and illustration are offered. Parakarstenia is characterized by its distinct suite of features, such as initially immersed, intracortical, later erumpent and seemingly superficial, sessile and usually gregarious apothecia with a flat to slightly convex, greyish white or pale brown disc; a hairless, buff to yellow receptacle; a non-protruding margin, absent periphysoids and crystals, cylindrical to clavate asci with conical apex and a hemiamyloid (type RR) outer wall; and narrowly cylindrical-clavate to fusoid, vermiform, straight to medium curved, initially non-septate, at maturity transversely multiseptate ascospores. An updated phylogram for Ostropales with selected, predominantly non-lichenized members based on multigene analysis is provided.

The only hitherto known species of the monotypic genus Tromeropsis, the rarely reported T. microtheca, is redescribed from recent collections on mostly little decayed, grayed, xeric, sun-exposed wood of decorticated trunks and branches of different gymnosperms, exceptionally angiosperms, from different humid regions of central Europe and a dry area in Macaronesia. Two further, very similar species are here newly described from decayed xeric wood of different angiosperm trees and shrubs from dry to arid regions of North America, Australia, and Macaronesia. Characteristics of the genus are: black sessile apothecia, dark olivaceous exudate, fissitunicate multi-spored asci, minute, cylindrical to ellipsoid, hyaline ascospores, a yeast-like asexual morph, and, in some species, a synanamorph with allantoid conidia formed on integrated conidiogenous cells reminiscent of the genus Lecythophora but with holoblastic conidiogenesis. A lectotype is designated for the type species of the likewise sexually typified, monotypic, illegitimate genus Microspora, M. dura, which was re-examined from the original material and found to be a later synonym of T. microtheca. Nuclear rDNA data were obtained from two collections of T. microtheca and four collections of the two new species. DNA sequences of T. microtheca match those from asexual morph isolates or environmental samples in public databases. Different misapplied names attributed to sequences from asexual morph isolates gained from coniferous wood from northern Europe, North America, and eastern Asia were re-identified as T. microtheca. A very close relationship between Tromeropsis and the type species of the asexually typified genus Symbiotaphrina, S. buchneri, was observed. Independent molecular phylogenetic analyses of three rDNA regions (partial SSU, ITS, partial LSU) each place Tromeropsis and the type species of Symbiotaphrina in a single supported clade without showing clear limits between the two genera. Based on multigene analysis, Symbiotaphrina was recently placed together with the small order Xylonales in the new class Xylonomycetes. We here validate the order Symbiotaphrinales previously published as nom. nud. and describe the family Symbiotaphrinaceae. Since the name Symbiotaphrina was validated one year before Tromeropsis was published, and is more widely used, it is adopted here and T. microtheca combined into Symbiotaphrina. rDNA data further suggest that two members of the asexually typified genus Hyphozyma, H. lignicola and H. sanguinea, belong to Symbiotaphrina, whereas the type species of Hyphozyma, H. variabilis, clusters in the Thelebolales (Leotiomycetes), where it is a later synonym of Cleistothelebolus nipigonensis, the type species of Cleistothelebolus. The new combinations S. lignicola and S. sanguinea are proposed, to which the newly described species S. desertorum and S. larreae are added. Based on their close relationship and a similar yeast-like asexual morph in pure culture, we hypothesize that the life cycles of all these wood-inhabiting taxa include a symbiotic phase in the gut of arthropods and, conversely, we suppose that the life cycles of S. buchneri and S. kochii include unknown sexual morphs growing on plant substrate.

Fungi in the class Leotiomycetes are ecologically diverse, including mycorrhizas, endophytes of roots and leaves, plant pathogens, aquatic and aero-aquatic hyphomycetes, mammalian pathogens, and saprobes. These fungi are commonly detected in cultures from diseased tissue and from environmental DNA extracts. The identification of specimens from such character-poor samples increasingly relies on DNA sequencing. However, the current classification of Leotiomycetes is still largely based on morphologically defined taxa, especially at higher taxonomic levels. Consequently, the formal Leotiomycetes classification is frequently poorly congruent with the relationships suggested by DNA sequencing studies. Previous class-wide phylogenies of Leotiomycetes have been based on ribosomal DNA markers, with most of the published multi-gene studies being focussed on particular genera or families. In this paper we collate data available from specimens representing both sexual and asexual morphs from across the genetic breadth of the class, with a focus on generic type species, to present a phylogeny based on up to 15 concatenated genes across 279 specimens. Included in the dataset are genes that were extracted from 72 of the genomes available for the class, including 10 new genomes released with this study. To test the statistical support for the deepest branches in the phylogeny, an additional phylogeny based on 3156 genes from 51 selected genomes is also presented. To fill some of the taxonomic gaps in the 15-gene phylogeny, we further present an ITS gene tree, particularly targeting ex-type specimens of generic type species. A small number of novel taxa are proposed: Marthamycetales ord. nov., and Drepanopezizaceae and Mniaeciaceae fams. nov. The formal taxonomic changes are limited in part because of the ad hoc nature of taxon and specimen selection, based purely on the availability of data. The phylogeny constitutes a framework for enabling future taxonomically targeted studies using deliberate specimen selection. Such studies will ideally include designation of epitypes for the type species of those genera for which DNA is not able to be extracted from the original type specimen, and consideration of morphological characters whenever genetically defined clades are recognized as formal taxa within a classification. Electronic supplementary material The online version of this article (10.1186/s43008-019-0002-x) contains supplementary material, which is available to authorized users.

This study focuses on the genus Encoelia and the subfamily Encoelioideae in the morphologically and ecologically diverse Helotiales. The 28S and 18S rDNA as well as tef1, rpb1 and rpb2 were sequenced for 70 species. Phylogenetic analyses revealed Encoelia and Encoelioideae to be highly polyphyletic, with species distributed among eight major lineages. Encoelia fascicularis and E. pruinosa belonged to Sclerotiniaceae and were combined in a new genus, Sclerencoelia. Rutstroemiaceae comprised E. tiliacea and Dencoeliopsis johnstonii, both accepted in Rutstroemia. The type of Encoelia, E. furfuracea, was closely related to species of Velutarina, Cenangiopsis and Crumenulopsis. These species together with members of Hemiphacidiaceae formed a clade conforming to the emended concept of Cenangiaceae, introduced here. Another resurrected family, Cordieritidaceae, comprised E. fimbriata, E. heteromera and species of Ameghiniella, Cordierites, Diplocarpa and Ionomidotis, characterised by inamyloid asci and a positive ionomidotic reaction. Encoelia glauca showed closest affinities with Chlorociboria species in Chlorociboriaceae. A new genus, Xeropilidium, with sporodochial and pycnidial synanamorphs, was described for the distinct encoelioid member of the Chaetomellaceae, previously known as E. fuckelii. Morphological and ecological synapomorphies were distinguished from convergent characters to delimit monophyletic taxa including encoelioid fungi. Incorporation of public sequences from various biological samples in ITS rDNA analyses allowed identification of sequenced organisms at species, genus, or family level and added information on the ecology of seversal taxa. Members of Cenangiaceae appeared to be widespread as endophytes. Inclusion of encoelioid genera in Chaetomellaceae and Sclerotiniaceae added xylicolous saprotrophs to these families.

A new species of Orbilia related to O. luteorubella is described mainly based on morphological characters of its asexual morph and molecular data. The sexual morph does not significantly differ from O. luteorubella, whereas the asexual morph obtained from its ascospore isolate resembles members of the non-predacious genus Dactylella, because it has fusiform phragmoconidia borne singly at the apex of conidiophores. Phylogenetic analysis showed that this strain clustered with a clade that included available strains of the O. luteorubella aggregate and was distant from all analysed Dactylella species. Within this clade, the new strain fell between species with filiform conidia and those of a Pseudotripoconidium anamorph. By combining morphological and phylogenetic analyses, we conclude that our isolate belongs to a new taxon. Pleomorphism of the new taxon is described and discussed.

A list of all generic names that have been connected with the Orbiliomycetes is provided. Recommendations are made as to which names should be used in accordance with the rules and the different generic concepts. There is a mismatch in the current generic concepts within Orbiliomycetes regarding the two morphs: a narrow concept is used for the asexual morphs, but a broad concept relies on the sexual morphs. As a consequence, many more generic names have been established for the asexual morphs. A number of previous generic concepts are artificial, since they were based on single characters without molecular support. In order to provide solutions for this mismatch, we present three different generic concepts within the Orbiliomycetes. A broad concept recognizes a large genus Orbilia, with which most of the listed names fall into synonymy, but could be maintained as infrageneric names. Due to the lack of data proving phylogenetic relationships, this broad concept, at present, is the most practicable and recommended one. A moderate concept subdivides Orbilia into several genera, with all nematode-trapping fungi merged in Arthrobotrys. A narrow generic concept accepts genera based on differences in trapping organs, but also subdivides the remaining groups of Orbilia into additional genera. Trapping of invertebrates (zoophagy) is not restricted to Arthrobotrys in a broad sense, but occurs also in the more distant basal genera Hyalorbilia and Lecophagus, which mainly prey on rhizopods and rotifers. Whether these predatory capabilities trace back to a common ancestor is not clear. The following new combinations are proposed: Hyalorbilia oviparasitica, Hyalorbilia quadridens, Hyalorbilia tenuifusaria, and Orbilia fissilis.

Five species of Hymenoscyphus that fruit on black stromatized parts of dead leaves of deciduous trees are presented, giving details on their morphological and ecological characteristics. Several of these species have previously been misplaced in rutstroemiaceous genera because of the presence of a substratal stroma. However, the heteropolar, scutuloid ascospores with an often hook-like lateral protrusion at the rounded apex and the ascus apical ring of the Hymenoscyphus-type represent two reliable morphological characteristics that, together with molecular data, provide clear evidence for their placement in the genus Hymenoscyphus (Helotiaceae). Among the species treated is Hymenoscyphus fraxineus (=Hymenoscyphus pseudoalbidus), the causal agent of the European ash dieback disease. Since 1992 this species started within Europe to replace the rather uncommon Hymenoscyphus albidus, which is likewise confined to leaves of Fraxinus. Hy. fraxineus has been recorded already since 1990 in Eastern Asia (Japan, Korea, northeast of China), where it had been initially misidentified as Lambertella albida (≡Hy. albidus). In these regions, it occurs as a harmless saprotroph on Fraxinus mandshurica and Fraxinus rhynchophylla, suggesting that those populations are native while the European ash dieback disease has a recent Eastern Asiatic origin. The distinctly higher genetic diversity found in Japanese Hy. fraxineus in contrast to European Hy. fraxineus supports this view. Genetic similarities between Japanese Hy. fraxineus and European Hy. albidus suggest that also Hy. albidus might be a descendant of Asian Hy. fraxineus, though having invaded Europe much earlier. However, consistent genetic deviation between European and Asian Hy. fraxineus at two nucleotide positions of the ITS region indicates that the European ash disease originates from a region different from the presently known areas in Eastern Asia. Our results underline the importance of detailed morphological studies in combination with molecular work. Hy. fraxineus was described from Europe as a cryptic species that differed from Hy. albidus by molecular data alone. However, the Hy. albidus/Hy. fraxineus species complex represents one of many examples within the ascomycetes in which subtle microscopic differences between closely related species, in this case the presence or absence of croziers at the ascus base, are strictly correlated with molecular characteristics. Two species that closely resemble Hy. albidus and Hy. fraxineus form pseudosclerotia in Aesculus leaves and again differ from each other mainly in the ascus base: Hymenoscyphus aesculi on Aesculus hippocastanum from Europe lacks croziers, whereas Hymenoscyphus honshuanus from Japan on Aesculus turbinata possesses croziers. Other taxa treated here include Hymenoscyphus vacini, a European species growing on stromatized net veins of skeletonized leaves of Acer, and Hymenoscyphus torquatus, a Chinese species on unidentified herbaceous stems. An equivalent stroma-forming North American species on leaves of Fraxinus, Rutstroemia longipes (Rutstroemiaceae), is discussed and compared. A key to the Hymenoscyphus species that form a dark stroma on leaves of Acer, Aesculus, Fraxinus, and Picrasma is provided.

he discomycete Hymenoscyphus subcarneus was found to grow parasitic on the liverwort Cephalozia catenulata in the Białowieża National Park (Poland), and is described and illustrated from the fresh collection. Two characters, the ascus apical ring structure of the Calycina type and the contents of the living paraphyses (multiguttulate by low-refractive vacuolar bodies), have not been reported previously. In addition, a dried collection on Pohlia gracilis from Switzerland, Grimsel area, was studied. The relationship, taxonomy and infraspecific variation of the fungus are discussed. A new genus, Roseodiscus, is established to accomodate this bryicolous fungus together with two very similar equiseticolous species, Hymenoscyphus rhodoleucus and H. equisetinus. The three species are macroscopically characterized in the fresh state by a pale rosaceous-lilaceous hymenium and a mostly slender, concolorous or whitish stipe. Roseodiscus resembles Hymenoscyphus in various respects, but sharply deviates in the apical ring type which appears to indicate a more close relationship with genera like Calycina or Stamnaria. Rhizoscyphus ericae which forms a mycorrhiza with roots of Ericaceae, is compared with Roseodiscus. Based on vital observations of R. ericae this species is believed to be congeneric with the type of Pezoloma, P. griseum.

The genus Orbilia Fr. (Orbiliaceae Nannf.) was currently thought to comprise some dozens of species, being particularly common in temperate regions on woody substrates in moist habitats. During monographic work on the family Orbiliaceae over many years by the second author, species diversity turned out to be extremely higher, with presently about 330 species of Orbilia, and a strong preference of semihumid to arid, subtropical to tropical vegetation zones. The characterization of the genus and classification history of Orbiliaceae has been reviewed, e.g., in Liu et al. (2005) and Zhang et al. (2007, 2009).

Xerombrophila, a new member of the Helotiales, is erected for a previously undescribed species that macroscopically resembles genera such as Phaeohelotium or Pezicula. The new species, for which we propose the name X. crystallifera, is characterized by a strong gelatinization of the medullary excipulum as well as the covering layer of the ectal excipulum, by the presence of abundant octahedral crystals, asci with an euamyloid apical ring that resembles the Calycina-type, and paraphyses containing refractive vacuoles. It can also be distinguished from members of both Ombrophila and Phaeohelotium in that it is desiccation-tolerant by surviving several weeks in the dry state. The species appears to be confined to xeric bark of Salix and was exclusively found over waterlogged soil, irrespective of being acidic or calcareous. It is known from various planar and colline areas of temperate Europe, and can be found throughout the year. Phylogenetic analysis of partial LSU sequences positions X. crystallifera as a sister taxon of a clade within the Helotiaceae s.l. that includes Ascocoryne, Chloroscypha, Gelatinodiscus, Neobulgaria and "Sarcoleotia" turficola.

Colipila, a new member of the Helotiales, is erected for two previously undescribed lignicolous species resembling Dasyscyphella and Lachnum by macroscopy. Species of Colipila are characterized by their long, entirely smooth, hyaline, thin-walled, multiseptate, subulate to basally fusoid hairs that tend to be curved on the stipe and lower flanks, and dimorphic, partly strongly protruding paraphyses which closely resemble the hairs. The type species, C. masduguana, is recorded repeatedly in southern France on rotten decorticated branches and trunks of Castanea sativa on the moist forest floor in sub-Mediterranean regions with siliceous soils, but also once on Quercus robur in a temperate forest with calcareous soil. The second species, C. pilatensis, was found on wood of an unidentified member of Rosaceae in a calcareous region of the Northern Alps and is known only from the holotype. The phylogenetic position of C. masduguana within the Helotiales was not resolved based on the analysis of nuclear LSU ribosomal DNA sequences. A key to the species of Colipila is provided.

The monotypic genus Fuscoscypha possesses hairs similar as in the genus Hyaloscypha but differs by grey-olivaceous-brown apothecia with short dark stipes. Molecular data proves that the pigmentation does not permit delimitation of a separate genus, as white and brown taxa do not form separate clades. Followingly, Fuscoscypha is here considered to be a synonym of Hyaloscypha. Three of the here treated four species have an olivaceous-brown excipulum. Two are saprophytes on decaying leaves and fruits of angiosperms: F. acicularum, the type species of Fuscoscypha, and Hyaloscypha fuscostipitata comb. nov. (formerly placed in Betulina). Two are biotrophic parasites on Bryophyta: Hyaloscypha hepaticola comb. nov. (formerly placed in Trichopeziza) and the hyaline-excipled Hyaloscypha albocarpa spec. nov. which is otherwise very similar to H. hepaticola. The type species of the genus Betulina, B. hirta, is found to be an earlier synonym of Urceolella salicicola (= U. graddonii). The new combination Urceolella hirta is therefore proposed, hence Betulina is considered a synonym of Urceolella.

A new species of the genus Orbilia, O. yuanensis (Orbiliales, Orbiliomycetes), was collected from Yunnan Province (China) and Taiwan. The fungus differs from previously known Orbilia species in that it has rod-shaped ascospores with a tear-shaped spore body. An anamorph that was obtained from ascospore isolates is characterized as producing long, curved macroconidia and much smaller, partly helicoid microconidia. Morphologically, this anamorph fits the polyphyletic genus Anguillospora. Based on a sequence analysis of the internal transcribed spacer region (ITS) gained from two isolates, O. yuanensis nested near species of the Orbilia luteorubella aggregate, although at a rather high distance. To date, there have been two reports regarding a connection between Orbilia species and their Anguillospora anamorph. The connection between O. yuanensis and its Anguillospora anamorph discussed here is the third published report. In this paper, both teleomorph and anamorph are illustrated and described.

The new rules formulated in Article 59 of the International Code of Nomenclature for algae, fungi, and plants (ICN) will cause numerous, often undesirable, name changes, when only phylogenetically defined clades are named. Our task is to name fungal taxa and not just clades. Two suggestions are made here that may help to alleviate some disadvantages of the new system. (1) Officially an epithet coined in a list- demoted genus that is older than the oldest one available in the list-accepted genus would have to be recombined in the accepted genus. We recommend that individual authors and committees establishing lists of protected names should generally not recombine older epithets from a demoted genus into the accepted genus, when another one from pre-2013 is available in that genus. (2) Because the concepts of correlated teleomorph and anamorph genera are often incongruent, enforced congruence leads to a loss of information. Retaining the most suitable generic name is imperative, even when this is subordinated to another, list-accepted, generic name. Some kind of cryptic dual generic nomenclature is bound to persist. We therefore strongly recommend the retention of binomials in genera where they are most informative. With these recommendations, the upheaval of fungal nomenclature ensuing from the loss of the former Art. 59 can be reduced to an unavoidable minimum.

O. laevimarginata is here described as a new species, and also its asexual morph could not be assigned to an existing taxon. Anamorphic strains were obtained from three teleomorph specimens which were collected at different sites and dates. The anamorph is characterized by cylindric-ellipsoid to oblong conidia, mainly 1-septate, growing either singly or mostly from 2–10 denticles in a capitate arrangement on the tip of conidiophores. These morphological characters are similar to those of the nematophagous anamorph genus Arthrobotrys , but the present isolates lack the ability to produce any trapping devices when contacting with nematodes. Phylogenetic analysis inferred from ITS rDNA sequences on different groups within Orbilia showed that the isolates of O. laevimarginata clustered together in a clade separate from Orbilia crenatomarginata (= Hyalinia crystallina ). The two species are close to O. scolecospora and an undescribed species, which all have a crenulate to dentate apothecial margin composed of solid glassy processes. The group clustered distant from those species identified within the nematode-trapping anamorph genera Arthrobotrys , Dactylellina and Drechslerella , but also distant from the non-predacious anamorph genus Dactylella . By combining morphological and phylogenetic analysis, we conclude that the three isolates belong to a single undescribed holomorph species. The morphological differences among the three isolated anamorphic strains, and phylogenetic divergence of nematode-trapping fungi and related species are discussed.