Publications

2022
Bradshaw, M., et al., 2022. Secondary DNA Barcodes (CAM, GAPDH, GS, and RpB2) to Characterize Species Complexes and Strengthen the Powdery Mildew Phylogeny. Frontiers in Ecology and Evolution. Publisher's VersionAbstract
Powdery mildews are a group of economically and ecologically important plant pathogens. In the past 25 years the use of ribosomal DNA (rDNA) in the powdery mildews has led to major taxonomic revisions. However, the broad scale use of rDNA has also revealed multiple species complexes that cannot be differentiated based on ITS + LSU data alone. Currently, there are only two powdery mildew taxonomic studies that took a multi-locus approach to resolve a species complex. In the present study, we introduce primers to sequence four additional regions (CAM, GAPDH, GS, and RPB2) that have the potential to improve support values in both broad and fine scale phylogenetic analyses. The primers were applied to a broad set of powdery mildew genera in China and the United States, and phylogenetic analyses included some of the common complexes. In taxa with nearly identical ITS sequences the analyses revealed a great amount of diversity. In total 154 non-rDNA sequences from 11 different powdery mildew genera were deposited in NCBI’s GenBank, laying the foundation for secondary barcode databases for powdery mildews. The combined and single loci phylogenetic trees constructed generally followed the previously defined species/genus concepts for the powdery mildews. Future research can use these primers to conduct in depth phylogenetic, and taxonomic studies to elucidate the evolutionary relationships of species and genera within the powdery mildews.
Mitchell, J.K., et al., 2022. Species of the common discomycete genus Bisporella reassigned to at least four genera. Mycologia. Publisher's VersionAbstract
Bisporella as typically conceived is a genus of noticeable, bright yellow inoperculate discomycetes. This interpretation of the genus, however, is at odds with Bisporella pallescens, the current name of the type species of the genus; furthermore, the genus has been interpreted as including the unusual species Bisporella resinicola. By comparing morphological and molecular traits of species traditionally included in Bisporella, we show that the genus is polyphyletic, with many “typical” members of the genus belonging instead in Calycina in Pezizellaceae. Bisporella pallescens is conclusively linked with its asexual morph, Bispora antennata, and the genus Bisporella is abandoned as a later synonym of the monotypic genus Bispora (previously applied only to asexual fungi) and placed as sister to Hymenoscyphus in Helotiaceae. Bisporella resinicola is shown to represent an independent monotypic genus, Eustilbum, which so far is placed incertae sedis in Helotiales. Finally, “Bisporella” subpallida, like Bispora, belongs to Helotiaceae but is instead related to “Phaeohelotium” epiphyllum.
Pfister, D.H., et al., 2022. A reexamination and realignment of Peziza sensu lato (Pezizomycetes) species in southern South America/Un reexamen y revisión de las especies de Peziza sensu lato (Pezizomycetes) en el cono sur de Sudamérica. Darwiniana , 10 (1) , pp. 148-177. Publisher's VersionAbstract

In this study we review recent collections and historical records of epigeous members of the Pezizales formerly placed in the large, heterogenous genus Peziza from temperate southern South America. Recent analyses using molecular phylogenetic methods allow placement of these species in several previously described genera in recognition of the heterogeneity of Peziza. We include species in nine genera, describe one new species (Peziza gamundiae sp. nov.), and propose one new combination (Phylloscypha nothofageti comb. nov.). We also demonstrate that Pustularia microspora is a synonym of the previously described taxon Peziza pseudosylvestris. Our purpose is to draw attention to these taxa in order to promote their collection and study in a modern framework.

En este trabajo hemos revisado material fresco y colecciones históricas de Pezizales epigeos formalmente incluidos en el amplio y heterogéneo género Peziza provenientes de las zonas templadas del sur de Sudamérica. Estudios recientes basados en filogenias moleculares han permitido posicionar estas especies en varios géneros previamente descritos demostrando su heterogeneidad. Incluimos aquí especies de nueve géneros, una especie nueva para la ciencia (Peziza gamundiae sp. nov.) y proponemos una nueva combinación (Phylloscypha nothofageti comb. nov.). También demostramos que Pustularia microspora es sinónimo de un taxón previamente descrito como Peziza pseudosylvestris. Nuestro objetivo es llamar la atención sobre la presencia de estos taxa para promover su recolección y estudio en trabajos científicos modernos.

Nokes, L.F., Haelewaters, D. & ., P.D.H., 2022. Exploration of Marine Lichenized Fungi as Bioindicators of Coastal Ocean Pollution in the Boston Harbor Islands National Recreation Area. Rhodora , 122 (992) , pp. 251–273. Publisher's VersionAbstract
This preliminary exploration of marine lichenized fungi (lichens) as bioindicators of water pollution examined the distribution of intertidal lichen communities in the Boston Harbor Islands National Recreation Area with respect to recorded pollution throughout the harbor. We found significant negative associations between pollution measurements and the health of the lichen community based on cover and species richness. We also observed significant differences in species composition between areas of higher pollution and areas of lower pollution, though not enough data are available to establish the pollution sensitivity or tolerance of individual species. We note that difficulties in the collection and identification of marine lichens hamper efforts to use them broadly as bioindicators. This study suggests that marine lichens could prove useful as bioindicators, but more research is needed to understand the differential effects of pollution on individual species as well as to establish practical procedures both for quantifying marine lichen community health and for widespread bioindication using marine lichens. Finally, one species collected during this study, Verrucaria ceuthocarpa, represents a first report for the Boston Harbor Islands National Recreation Area.
Bradshaw, M., Braun, U. & Pfister, D.H., 2022. Powdery mildews on Quercus: A worldwide distribution and rediscovered holotype provide insights into the spread of these ecologically important pathogens. Forest Pathology. Publisher's VersionAbstract
Powdery mildew, caused by Erysiphe spp., on oak has been shown to have serious ecological consequences on Quercus hosts. Erysiphe alphitoides and Equercicola are two of the most heavily studied and common powdery mildews known to occur on Quercus species. In recent years, these species have been noted throughout the world on a range of hosts within and outside the Quercus genus. Reports that Ealphitoides was absent in European herbaria before 1921 and the discovery of the holotype of Ealphitoides from 1911 in an American herbarium (FH) led to the current study in which we genetically analysed six specimens of Ealphitoides s. lat including, most importantly, the holotype of Ealphitoides from France collected in 1911. The results of our analyses revealed that: (1) The sequence of the Ealphitoides holotype falls within the Equercicola clade, confirming that Ealphitoides did not spread to Europe until ~1921. (2) Ealphitoides var. chenii forms a monophyletic clade with Eepigena and should be reduced to synonymy with that species and (3) through sequence analyses Ealphitoides and Equercicola are confirmed to have spread to North America. The sequencing results of the Ealphitoides holotype have severe nomenclatural-taxonomic consequences. A proposal was submitted simultaneously with the present manuscript to conserve the name Ealphitoides so that the traditional usage of the names Ealphitoides and Equercicola could be maintained. The sequences obtained for the current study provide new insight into the taxonomy and spread of these ecologically significant, globally distributed species. The present study highlights the importance of sequencing specimens from type material, above all when morphological similar species are involved.
Quijada, L., et al., 2022. Apothecial Ancestry, Evolution, and Re-Evolution in Thelebolales (Leotiomycetes, Fungi). Biology , 11 (583) , pp. 1-28. Publisher's VersionAbstract
Closed cleistothecia-like ascomata have repeatedly evolved in non-related perithecioid and apothecioid lineages of lichenized and non-lichenized Ascomycota. The evolution of a closed, darkly pigmented ascoma that protects asci and ascospores is conceived as either an adaptation to harsh environmental conditions or a specialized dispersal strategy. Species with closed ascomata have mostly lost sterile hymenial elements (paraphyses) and the capacity to actively discharge ascospores. The class Leotiomycetes, one of the most speciose classes of Ascomycota, is mainly apothecioid, paraphysate, and possesses active ascospore discharge. Lineages with closed ascomata, and their morphological variants, have evolved independently in several families, such as Erysiphaceae, Myxotrichaceae, Rutstroemiaceae, etc. Thelebolales is a distinctive order in the Leotiomycetes class. It has two widespread families (Thelebolaceae, Pseudeurotiaceae) with mostly closed ascomata, evanescent asci, and thus passively dispersed ascospores. Within the order, closed ascomata dominate and a great diversity of peridia have evolved as adaptations to different dispersal strategies. The type genus, Thelebolus, is an exceptional case of ascomatal evolution within the order. Its species are the most diverse in functional traits, encompassing species with closed ascomata and evanescent asci, and species with open ascomata, active ascospore discharge, and paraphyses. Open ascomata were previously suggested as the ancestral state in the genus, these ascomata depend on mammals and birds as dispersal agents. In this scheme, species with closed ascomata, a lack of paraphyses, and passive ascospore discharge exhibit derived traits that evolved in adaptation to cold ecosystems. Here, we used morphological and phylogenetic methods, as well as the reconstruction of ancestral traits for ascomatal type, asci dehiscence, the presence or absence of paraphyses, and ascospore features to explore evolution within Thelebolales. We demonstrate the apothecial ancestry in Thelebolales and propose a new hypothesis about the evolution of the open ascomata in Thelebolus, involving a process of re-evolution where the active dispersal of ascospores appears independently twice within the order. We propose a new family, Holwayaceae, within Thelebolales, that retains the phenotypic features exhibited by species of Thelebolus, i.e., pigmented capitate paraphyses and active asci discharge with an opening limitation ring
Braun, U., Bradshaw, M. & Pfister, D.H., 2022. (2863) Proposal to conserve the name Golovinomyces against Euoidium (Ascomycota: Erysiphaceae). Taxon , 71 (2) , pp. 459. Publisher's Version
Braun, U., Bradshaw, M. & ., P.D.H., 2022. (2864) Proposal to conserve the name Microsphaera alphitoides (Erysiphe alphitoides) (Ascomycota: Erysiphaceae) with a conserved type. Taxon. Publisher's Version
2021
Healy, R.A., et al., 2021. Endophytism and endolichenism in Pezizomycetes: the exception or the rule?. New Phytologist. Publisher's Version PDF
Ribes, M.A., et al., 2021. Wanted on Agave americana! Hymenobolus agaves, an overlooked introduced pathogen in the western palearctic region. Fungal Systematics and Evolution , 8 , pp. 129-142. Publisher's VersionAbstract
Hymenobolus agaves has been reported only in Europe and Africa on the American plant Agave americana (Asparagaceae). This fungus has never been found in the native range of its host, in arid ecosystems of northern and central Mexico and Texas, USA. It has been suggested to be a pathogen that can kill its host. The fungus grows on succulent leaf bases of the plant. The morphology – black apothecia with a hymenium that disintegrates when asci mature and dark ornamented ascospores – make this species very distinctive, but it has been collected and reported only a few times since its first description. Its systematic position has been unclear, and it has been treated as incertae sedis, that is of uncertain placement, in Leotiomycetes. With recent collections and additional data on the ecology of H. agaves, we use integrative taxonomy (DNA sequences, morphology, ecology) to show its relationships is with Cenangiaceae.
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Karakehian, J.M., et al., 2021. Methods for observing, culturing, and studying living ascospores. Asian Journal of Mycology , 4 (2) , pp. 1-18. Publisher's VersionAbstract
Ascospore morphologies provide important characters with which to diagnose and describe taxa in Ascomycota. Ascospore features such as size, shape, color, septation, wall thickness, and guttulation, among others, are provided in identification manuals and descriptions of new species. Yet, by tradition, ascospores are usually described from dead fungarium material, and unfortunately, occasionally from immature or overmature ones. However, living, mature ascospores display a wealth of taxonomically informative morphological features that are lost or obscured when they die. Examples of the severe morphological changes that ascospores undergo when they die are provided here. Data from living ascospores may not be observed and recorded by mycologists because field and laboratory practices do not prioritize the study of freshly collected specimens. In this review, we discuss how to assess ascospore maturity and describe methods to produce an ascospore deposit for the purpose of obtaining living, mature ascospores. Ascospores are ejected from living, mature asci onto a cover glass or growth medium. The ascospores collected on these surfaces can be used in microscopy and culture studies. Notes on a method for isolating conidia on growth medium are also provided. This guide is aimed at those who have a basic understanding of ascomycetes, including the various types of ascomata and mechanisms of ascospore liberation. Methods given in this paper are primarily applied to ascomycete fungi that have active ascospore discharge. Some methods may be adapted for use with other groups that have passive discharge. Our purpose is to promote standardized, accurate, and thorough morphological characterization of living ascospores, as well as to encourage the routine employment of culture-based methods.
Voitk, A., Lebeuf, R. & Pfister, D.H., 2021. Peziza nivalis - constant species or species complex?. OMPHALINA , XII (3). PDF
Pfister, D.H. & Healy, R.A., 2021. Pezizomycetes. In Encyclopedia of Mycology. Elsevier.Abstract
Introduction The Pezizomycetes comprise a single order, Pezizales, with > 22 families currently recognized. Along with the Orbiliomycetes, the class represents one of the basal lineages among the filamentous Ascomycota (Shen et al., 2020). The class is thought to have originated between 400 and 540 mya (Beimforde et al., 2014; Martin et al., 2010; Murat et al., 2018). The full diversity of the order has yet to be completely documented since previously undetected lineages continue to be found through application of molecular methods. There are approximately 200 genera and perhaps 2000 species. Ascomata are epigeous (above ground), or hypogeous (below ground). The truffles of commerce belong to this latter group. The epigeous ascomata are apotl1ecial, deistothecial or are highly reduced. The reduced forms are composed of only a few asci in dusters on vegetative hyphae with little or no sterile supporting tissue ( excipulum). In the ep,lppigeous lineages, ascospores are generally forcibly released by an opening at the ascus apex resulting in the formation of an operculum, or lid. Hypogeous members occur in several of the families. There are at least 30 independent origins of truffle-like members (Alvarado et al., 2011, 2016; Cabera et al., 2016; Grupe et al., 2019; llansen et al., 2013; Kraisitu­domsook et al., 2019; Kumar et al., 2017; Laessoe and Hansen, 2007; Smith, 2014; Smith and Healy, 2009; Trappe et al., 2010)
Mitchell, J.K., et al., 2021. Sareomycetes: more diverse than meets the eye. IMA Fungus , 12 (6). Publisher's VersionAbstract

Since its resurrection, the resinicolous discomycete genus Sarea has been accepted as containing two species, one with black apothecia and pycnidia, and one with orange. We investigate this hypothesis using three ribosomal (nuITS, nuLSU, mtSSU) regions from and morphological examination of 70 specimens collected primarily in Europe and North America. The results of our analyses support separation of the traditional Sarea difformis s.l. and Sarea resinae s.l. into two distinct genera, Sarea and ZythiaSarea as circumscribed is shown to comprise three phylospecies, with one corresponding to Sarea difformis s.s. and two, morphologically indistinguishable, corresponding to the newly combined Sarea coeloplataZythia is maintained as monotypic, containing only a genetically and morphologically variable Z. resinae. The new genus Atrozythia is erected for the new species A. klamathicaArthrographis lignicola is placed in this genus on molecular grounds, expanding the concept of Sareomycetes by inclusion of a previously unknown type of anamorph. Dating analyses using additional marker regions indicate the emergence of the Sareomycetes was roughly concurrent with the diversification of the genus Pinus, suggesting that this group of fungi emerged to exploit the newly-available resinous ecological niche supplied by Pinus or another, extinct group of conifers. Our phylogeographic studies also permitted us to study the introductions of these fungi to areas where they are not native, including Antarctica, Cape Verde, and New Zealand and are consistent with historical hypotheses of introduction.

Iturriaga, T., et al., 2021. First collection of the asexual state of Trichaleurina javanica from nature and the placement of Kumanasamuha. Asian Journal of Mycology , 4 (1) , pp. 19-28. Publisher's VersionAbstract
Ascomata of Trichaleurina javanica (Pezizomycetes) are encountered frequently in nature in tropical Asia. Its anamorphic state has been described previously as similar to Kumanasamuha. Our study describes the unusual anamorphic fungal specimen, MOZ170, collected from Gorongosa National Park, Mozambique. The fungal strain MOZ170 is identified using ribosomal DNA sequence data, its morphology is described, and morphological differences between the naturally growing anamorph and in vitro derived culture are compared. Phylogenetic placement of Kumanasamuha sundara was also determined using available data. The internal transcribed spacer (ITS) and partial large ribosomal subunit (LSU) were sequenced. Phylogenetic analyses of LSU supported MOZ170 as the anamorph of T. javanica, and revealed the proper placement of the type species of Kumanasamuha, i.e., K. sundara, within the Dothideomycetes. MOZ170 is characterized by its dark conidiophores growing in tufts, and conidia with curved, appressed crests and ridges. The comparison between naturally growing and in vitro grown cultures showed that the in vitro cultured anamorph had larger conidiogenous cells, larger conidia, and longer and more numerous lateral fertile branches compared to the fungus in nature. The present report represents the first anamorph collected from nature for this genus and one of the few natural collections of the anamorphic state within Chorioactidaceae with the exception of those of Desmazierella species.
Gómez-Zapata, P.A., et al., 2021. Notes on Trochila (Ascomycota, Leotiomycetes), with new species and combinations. MycoKeys , (78) , pp. 21-47. Publisher's VersionAbstract

Full Citation:

Gómez-Zapata P.A., D. Haelewaters, L. Quijada, D.H. Pfister and M.C. Aime. 2021. Notes on Trochila (Ascomycota, Leotiomycetes), with new species and combinations. MycoKeys 78: 21-47.

 

Studies of Trochila (Leotiomycetes, Helotiales, Cenangiaceae) are scarce. Here, we describe two new species based on molecular phylogenetic data and morphology. Trochila bostonensis was collected at the Boston Harbor Islands National Recreation Area, Massachusetts. It was found on the stem of Asclepias syriaca, representing the first report of any Trochila species from a plant host in the family Apocynaceae. Trochila urediniophila is associated with the uredinia of the rust fungus Cerotelium fici. It was discovered during a survey for rust hyperparasites conducted at the Arthur Fungarium, in a single sample from 1912 collected in Trinidad. Macro- and micromorphological descriptions, illustrations, and molecular phylogenetic analyses are presented. The two new species are placed in Trochila with high support in both our six-locus (SSUITSLSUrpb1rpb2tef1) and two-locus (ITSLSU) phylogenetic reconstructions. In addition, two species are combined in TrochilaTrochila colensoi (formerly placed in Pseudopeziza) and T. xishuangbanna (originally described as the only species in Calycellinopsis). This study reveals new host plant families, a new ecological strategy, and a new country record for the genus Trochila. Finally, our work emphasizes the importance of specimens deposited in biological collections such as fungaria.

K.Abarenkov,, et al., 2021. FungalTraits: a user-friendly traits database of fungi and fungus-like stramenopiles. Fungal Diversity. Publisher's VersionAbstract
Põlme, S., K. Abarenkov, R.H. Nilsson, B.D .Lindahl, K.E. Clemmensen, H. Kauserud, N. Nguyen, R. Kjøller, S.T.  Bates, P. Baldrian, T.G. Frøslev, K. Adojaan, A. Vizzini, A.Suija, D.H. Pfister, et al. 2021. FungalTraits: a user-friendly traits database of fungi and fungus-like stramenopiles. Fungal Diversity.


The cryptic lifestyle of most fungi necessitates molecular identification of the guild in environmental studies. Over the past decades, rapid development and affordability of molecular tools have tremendously improved insights of the fungal diversity in all ecosystems and habitats. Yet, in spite of the progress of molecular methods, knowledge about functional properties of the fungal taxa is vague and interpretation of environmental studies in an ecologically meaningful manner remains challenging. In order to facilitate functional assignments and ecological interpretation of environmental studies we introduce a user friendly traits and character database FungalTraits operating at genus and species hypothesis levels. Combining the information from previous efforts such as FUNGuild and FunFun together with involvement of expert knowledge, we reannotated 10,210 and 151 fungal and Stramenopila genera, respectively. This resulted in a stand-alone spreadsheet dataset covering 17 lifestyle related traits of fungal and Stramenopila genera, designed for rapid functional assignments of environmental studies. In order to assign the trait states to fungal species hypotheses, the scientific community of experts manually categorised and assigned available trait information to 697,413 fungal ITS sequences. On the basis of those sequences we were able to summarise trait and host information into 92,623 fungal species hypotheses at 1% dissimilarity threshold.

Haelewaters, D., Blackwell, M. & Pfister, D.H., 2021. Laboulbeniomycetes: Intimate Fungal Associates of Arthropods. Annual Review of Entomology , 66 (13) , pp. 1-20. Publisher's VersionAbstract
Arthropod–fungus interactions involving the Laboulbeniomycetes have been pondered for several hundred years. Early studies of Laboulbeniomycetes faced several uncertainties. Were they parasitic worms, red algal relatives, or fungi? If they were fungi, to which group did they belong? What was the nature of their interactions with their arthropod hosts? The historical misperceptions resulted from the extraordinary morphological features of these oddly constructed ectoparasitic fungi. More recently, molecular phylogenetic studies, in combination with a better understanding of life histories, have clearly placed these fungi among filamentous Ascomycota (subphylum Pezizomycotina). Species discovery and research on the classification of the group continue today as arthropods, and especially insects, are routinely collected and examined for the presence of Laboulbeniomycetes. Newly armed with molecular methods, mycologists are poised to use Laboulbeniomycetes–insect associations as models for the study of a variety of basic evolutionary and ecological questions involving host–parasite relationships, modes of nutrient intake, population biology, host specificity, biological control, and invasion biology. Collaboration between mycologists and entomologists is essential to successfully advance knowledge of Laboulbeniomycetes and their intimate association with their hosts.
2020
Haelewaters, D., et al., 2020. Mortality of native and invasive ladybirds co-infected by ectoparasitic and entomopathogenic fungi. PeerJ , 8 (e10110). Publisher's VersionAbstract
Harmonia axyridis is an invasive alien ladybird in North America and Europe. Studies show that multiple natural enemies are using Ha. axyridis as a new host. However, thus far, no research has been undertaken to study the effects of simultaneous infection by multiple natural enemies on Ha. axyridis. We hypothesized that high thallus densities of the ectoparasitic fungus Hesperomyces virescens on a ladybird weaken the host’s defenses, thereby making it more susceptible to infection by other natural enemies. We examined mortality of the North American-native Olla v-nigrum and Ha. axyridis co-infected with He. virescens and an entomopathogenic fungus—either Beauveria bassiana or Metarhizium brunneum. Laboratory assays revealed that He. virescens-infected O. v-nigrum individuals are more susceptible to entomopathogenic fungi, but Ha. axyridis does not suffer the same effects. This is in line with the enemy release hypothesis, which predicts that invasive alien species in new geographic areas experience reduced regulatory effects from natural enemies compared to native species. Considering our results, we can ask how He. virescens affects survival when confronted by other pathogens that previously had little impact on Ha. axyridis.
Baral, H.O., et al., 2020. Cryptic speciation in Orbilia xanthostigma and O. leucostigma (Orbiliomycetes): an aggregate with worldwide distribution. Mycological Progress , 20 , pp. 1503–1537. Publisher's VersionAbstract
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.

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