Thelocarpon periphysatum sp. nov. is described from marl quarries in the Netherlands. The species is characterized by perithecioid ascomata that have a green-yellowish ring around the ostiole, abundant periphyses and periphysoids that are up to 120 μm long, the absence of paraphyses and the wide, oblong and often somewhat asymmetrical ascospores. The perithecia are immersed in black cyanobacterial crusts on calcareous rocks. A worldwide key is provided to the 30 species of Thelocarpon that are currently accepted.

The new genus Nimisora Pérez-Ort., M. Svenss. & J. C. Zamora is introduced to accommodate a puzzling lecideoid epiphyte common in the central Iberian Peninsula. Nimisora is characterized by the following combination of characters: lecideoid apothecia, excipulum composed of sparingly branched radiating hyphae with narrow lumina, thick walls and swollen terminal cells, the presence of a brown K+ olivaceous green pigment in the epihymenium, an ascus tip similar to the Bacidia-type, and the presence of simple ellipsoid ascospores. Molecular analyses based on nrITS, nrLSU and mtSSU sequences unequivocally place the new genus within the Lecanoraceae; however, its phylogenetic affinities with other genera of the family remain largely unresolved. Comparisons with the morphologically closest genera are provided. The single species of the genus, Nimisora iberica Pérez-Ort., Turégano, M. Svenss. & J. C. Zamora sp. nov., is also described as new to science.

Arthonia epipolytropa Hafellner & Grube and Arthonia subclemens Hafellner, Grube & Muggia are described as new to science. Both are specific parasites of Lecanora polytropa s. lat., but of differing pathogenicity and of very different appearance. Whereas the clearly parasitic Arthonia epipolytropa with its agglomerated ascomata is presently known with certainty from a number of localities along the arch of the Alps (Austria, Italy, Switzerland), other parts of Europe (Norway, Albania) and northern America (USA), the less harmful A. subclemens with its isolated sunken ascomata is currently known only from a small number of localities in the Eastern Alps (Austria, Italy) and various mountain ranges in southern Europe (Spain, North Macedonia, Greece). The species are compared with other Arthonia species known from Lecanora or one of its recently segregated genera. A key to the fungi regularly found on Lecanora polytropa s. lat. is presented.

A new fruticulose species, Polycauliona comandorica, is described from the supralittoral zone of the Commander Islands in the Russian Far East. This growth form is very rare in the family Teloschistaceae where the new species belongs. It is the only fruticulose species of the family that forms vegetative propagules (soredia and blastidia). Polycauliona comandorica is similar to the North American P. thamnodes but differs in having a lighter yellow to grey thallus, longer and thicker branches with a rough surface, soredia and blastidia, and in lacking apothecia. Two fruticulose-lobate pairs of species in Polycauliona are briefly discussed: P. comandorica-P. verruculifera and P. thamnodes-P. brattiae.

A new lichen species is described from specimens growing on Fraxinus trees north of Eindhoven (the Netherlands). Morphological and genetic studies suggest that the new species belongs in the genus Catillaria, and the name Catillaria flexuosa is proposed because of its flexuose apothecia. The new species is characterized by the relatively large apothecia (up to 0.9 mm diam.) and relatively thick, knobby to ±subsquamulose, greenish, thallus. Due to their similar morphological features, C. flexuosa can be easily confused with Catillaria chalybeia, C. fungoides or C. nigroclavata, so it is therefore compared with these species. In addition, Arthonia epiphyscia is reported being a very rare species in the Netherlands.

Umbilicaria orientalis Davydov sp. nov. is described and phylogenetic analysis (ITS, mtLSU and RPB2) confirmed its distinctness and indicated a sister relationship with U. trabeculata within the U. vellea group. The species is morphologically similar to U. vellea but differs by simple, cylindrical or strap-like rhizinomorphs and by thalloconidia, developing both on the lower surface and on rhizinomorphs, that are 1–2 (rarely 4)–celled or in aggregates of up to 5–6 cells. Umbilicaria orientalis is described from the Russian Far East and is currently known from a wide range of localities in East Asia, from the Far East to South Siberia and Mongolia in the north, to Hebei and Tibet in the south. New sequences of U. americana were obtained; the species represents an independent phylogenetic lineage within Umbilicaria subg. Papillophora. Diagnostic traits and variability of different developmental stages of U. orientalis, as well as its East Asian distribution pattern, are discussed.

Fruticose lichens of the genus Usnea Dill. ex Adans. (Parmeliaceae), generally known as beard lichens, are among the most iconic epiphytic lichens in modern forest ecosystems. Many of the c. 350 currently recognized species are widely distributed and have been used as bioindicators in air pollution studies. Here we demonstrate that usneoid lichens were present in the Palaeogene amber forests of Europe. Based on general morphology and annular cortical fragmentation, one fossil from Baltic amber can be assigned to the extant genus Usnea. The unique type of cortical cracking indirectly demonstrates the presence of a central cord that keeps the branch intact even when its cortex is split into vertebrae-like segments. This evolutionary innovation has remained unchanged since the Palaeogene, contributing to the considerable ecological flexibility that allows Usnea species to flourish in a wide variety of ecosystems and climate regimes. The fossil sets the minimum age for Usnea to 34 million years (late Eocene). While the other similar fossils from Baltic and Bitterfeld ambers cannot be definitely assigned to the same genus, they underline the diversity of pendant lichens in Palaeogene amber forests.

Three species, Lobothallia brachyloba Paukov & I. V. Frolov, L. epiadelpha Paukov & A. Nordin and L. zogtii Paukov & Davydov, from arid regions of Eurasia (Russia, Kazakhstan, Kyrgyzstan, China and Mongolia) are described as new to science. Lobothallia brachyloba has flat, firmly attached lobes, immersed apothecia lacking a distinct thalline margin, and contains norstictic acid. Both Lobothallia epiadelpha and L. zogtii contain stictic acid and have a brown thallus and sessile apothecia. Lobothallia epiadelpha initially develops on crustose Circinaria spp, has thick lobes loosely attached to the substratum, and brown apothecial discs with constant thalline margins. Lobothallia zogtii is a free-living species with brownish black to jet black apothecial discs surrounded by a receding thalline margin. Lecanora bogdoënsis is synonymized with Lobothallia praeradiosa and Lobothallia helanensis is synonymized with L. subdiffracta. Three new combinations, Lobothallia hedinii (H. Magn.) Paukov, A. Nordin & Sohrabi, L. lacteola (Oxner) Şenkardeşler, Paukov, Davydov & Sohrabi, and L. subdiffracta (H. Magn.) Paukov, are proposed. Phylogenetic analyses of Lobothallia brachyloba, L. epiadelpha and L. subdiffracta (ITS, mtSSU) are presented, showing their relationships within Lobothallia. The lectotype of the name Aspicilia lacteola Oxner is designated. A key to 18 species of Lobothallia is provided.

The new species Ramalina fleigiae from Brazil is described growing on rocks in riverbeds in high altitude grasslands of southern Brazil. It grows in areas with constant water flow, sometimes almost immersed, and always in exposed habitats. Through an integrative approach, the detailed description of R. fleigiae includes morphological, anatomical, ecological, chemical and molecular data. Ribosomal DNA-based phylogenies suggest that R. fleigiae is more closely related to a species that shares its habitat preference (R. laevigata) than to the morphologically and chemically similar R. exiguella and R. gracilis. Ramalina fleigiae and R. laevigata can be distinguished by thallus morphology (irregularly flat branches in R. fleigiae vs. flat to canaliculate in R. laevigata) and pattern of chondroid tissue, as genetic distances between them are compatible with the interspecific range. It is possible that many species of Ramalina still remain hidden within the morphological or chemical variation of currently accepted species. Combining ecological, anatomical and molecular data will improve our future understanding of this genus.

Recently, nine species of lichenicolous fungi were found growing on Cetraria aculeata (Parmeliaceae) in a sand dune system in the Ukraine. One of them, Didymocyrtis trassii, is described here as new to science. This species is similar to D. pseudeverniae but differs in having smaller pycnidia, smaller obpyriform to clavate conidia as well as its DNA sequence. The new monotypic lichenicolous genus Katherinomyces is described here. Acremonium lichenicola s. l., Eonema pyriforme, Didymocyrtis cladoniicola and Lichenoconium erodens are reported for the first time on Cetraria aculeata. Furthermore, E. pyriforme is reported for the first time from lichen thalli. Acremonium lichenicola, E. pyriforme and Taeniolella rolfii are new for the mycobiota of the Ukraine. A key to the eleven known lichenicolous species on Cetraria aculeata is provided.

Sporastatia crassulata Yakovchenko & Davydov sp. nov. is described and a phylogenetic analysis (mtSSU) is presented, confirming its distinctness and indicating a sister relationship with S. testudinea. The species is unique among Sporastatia species in having a distinctly squamulose, thick, uneven thallus composed of convex, rounded squamules irregularly ascending in the central part of the thallus. The new combination Sporastatia karakorina (Poelt & Obermayer) Davydov & Yakovchenko is proposed. The type specimen of S. subasiatica was examined. A key to the six species of Sporastatia is given. Mountainous Central Asia appears to be the centre of species diversity and endemism for Sporastatia.

Species conservation depends on accurate data, but for many lichens existing collections are geographically biased and contain many taxonomic errors. It is unclear whether ‘non-expert’, systematic monitoring schemes can address these sources of error, particularly for taxonomically challenging lichens (e.g. species requiring chemistry for accurate identification). In this case study we use the Alberta Biodiversity Monitoring Institute (ABMI), a large-scale, systematic, multi-taxon monitoring programme, to better understand the ecology and distribution of a putative rare species, Cladonia rei. Collections of C. rei from Alberta dating from 1947 suggested the species was broadly distributed but rare, with seven accessioned specimens. We used comparative morphology, thin-layer chromatography and habitat modelling to compare historical records against more recent material from ABMI surveys. Contrary to the historical collections, ABMI samples suggest C. rei is almost entirely limited to the dry mixed grassland, northern fescue grassland and aspen parkland natural regions, and that within these ecosystems it is relatively common. The typical ecotype exhibited included a persistent primary thallus, podetia with a persistent basal cortex, and secondary squamules; typically they lacked cups, well-developed apothecia and fumarprotocetraric acid, and ramifications were sparse. Cladonia rei was consistently found in pastures and undisturbed grasslands that hosted relatively rich communities of epigeic lichens, thus it does not appear to act as a pioneer in Alberta or to commonly occupy the anthropogenic niches documented elsewhere. In summary, large-scale, systematic, non-targeted monitoring employing novices redressed issues of sample bias through almost 300 C. rei collections, simultaneously improving the ecological understanding of a putative rare species.

During lichenological explorations of tropical montane forests in Kenya, a remarkable new lichenicolous fungus was repeatedly found growing on thalli of the epiphytic tripartite cyanolichen Crocodia cf. clathrata. Molecular phylogenetic analyses placed the fungus within Gomphillaceae (Ostropales, Lecanoromycetes), a family mainly of lichen-symbiotic species in the tropics. The anatomical features (unitunicate, non-amyloid asci and simple, septate paraphyses) as well as the hemiangiocarpic ascoma development confirm its taxonomic affinity. DNA sequence data showed the closest relationship was with Gyalidea fritzei, followed by Corticifraga peltigerae. A monotypic genus, Taitaia, is introduced to incorporate a single species, T. aurea. The new fungus is characterized by aggregated ascomata with yellow margins and salmon red discs developing from a single base.

Bacidina mendax, described here as a new lichen species, appears to be common and widespread, at least in Central Europe. Analyses of the ITS rDNA region and the morphology of specimens showed an intraspecific variation in the new taxon. It differs from B. neosquamulosa in the lack of a subsquamulose thallus, and from B. caligans in its longer and only slightly curved to apically hooked conidia and lack of a granular (sorediate) thallus. Since ITS rDNA data support the inclusion of Bacidia pycnidiata Czarnota & Coppins in the genus Bacidina, a new combination is proposed.

Rhizocarpon smaragdulum Davydov & Yakovchenko sp. nov. is described and a phylogenetic analysis (ITS, mtSSU) is presented, confirming its distinctiveness and indicating a sister relationship with R. suomiense and R. subgeminatum. The species is unique among yellow Rhizocarpon species in having a single hyaline ascospore per ascus. The phylogenetic tree suggests that the number of ascospores per ascus has been reduced in Rhizocarpon more than once during the course of its evolution. Two new distributional records are also reported: Rhizocarpon atroflavescens is new for Siberia and R. norvegicum is new for the Altai Mountains. Rhizocarpon norvegicum in this region grows on rocks and is also lichenicolous on Acarospora bullata.

From the saprotrophs that decay plant material to the pathogens and mutualists that shape plant demography at local and regional scales, fungi are major drivers of tropical forest dynamics. Although endophytic fungi are abundant and diverse in many biomes, they reach their greatest diversity in tropical forests, where they can influence plant physiology, performance and survival. The number of quantitative studies regarding endophytes has increased dramatically in the past two decades, but general rules have not yet emerged regarding the biogeography, host affiliations, local or regional distributions, or phylogenetic diversity of endophytes in most tropical settings. Here, endophytic fungal communities associated with 18 species of eupolypod fern were compared among forest reserves in Panama, Costa Rica and Mexico. Molecular sequence data for >2000 isolates were used to determine the relationships of host taxonomy, forest (site), and environmental dissimilarity to endophyte community composition. Communities in related ferns differed significantly among forests, reflecting the interplay of geographic distance and environmental dissimilarity. Although the same phyla and classes of fungi were prevalent at each site, they differed in relative abundance. All sites were dominated by the same order (Xylariales), but sites differed in the phylogenetic clustering vs. evenness of their endophyte communities. By addressing the relationship of endophyte communities to host taxonomy, geographic distance and environmental factors, this study complements previous work on angiosperms and contributes to a growing perspective on the factors shaping communities of ecologically important fungi in tropical forests.

A diversity of filamentous microfungi was discovered from thallus surfaces of epiphytic lichens preserved in Bitterfeld and Baltic amber. We report seven distinct morphologies of dematiaceous hyphomycetes, some of which closely resemble species of the extant genera Sporidesmium, Taeniolella s. lat. and Taeniolina. Both the placement of the fungi on their substrates and the exquisite preservation of delicate structures indicate that the fungi were fully developed before they were engulfed by fresh resin. The lichens probably grew on the trunks of resin producing trees and became embedded in resin flows together with their fungal associates. The findings demonstrate that a wide range of presumably specialised fungi have lived on living and decomposing lichen thalli at least since the Paleogene. The findings add an interesting new component to the as yet poorly known mycota of the ancient European amber forests.

Two new species of Lichenothelia, both from Iran, are described. Lichenothelia iranica is characterized by a black thallus with often finely lobate, slightly effigurate, not areolate margins, eight non-amyloid spores per ascus and 1–3-septate ascospores with 1–2 longitudinal or oblique septa. Lichenothelia ilamensis is distinguished by a black areolate, fissured, slightly effigurate or rarely lobulate thallus. The areoles are confluent and aggregated in the centre, becoming dispersed towards the margin, and the asci contain (4–)6(–8) non-amyloid, 1-septate spores.

The coastline of Tabasco State in the Gulf of Mexico represents a highly deteriorated ecosystem, where densely populated human settlements and large offshore petroleum developments are negatively affecting the marine biodiversity. Previous work on marine ascomycetes reported that in the Gulf of Mexico the diversity of these fungi might be threatened by anthropogenic activities. Therefore we evaluated the diversity of marine ascomycetes in this area, and registered 19 taxa. Ceriosporopsis capillacea was recorded for the first time for Mexico. The highest diversity was obtained in the beach of Sánchez Magallanes, which receives a great quantity and diversity of organic remains originating from El Carmen/Machona mangrove forests via the Santa Ana mouth, benefiting the proliferation of marine fungi. The lowest diversity was documented in the beach of Paraíso, which is close to the delta of one of the most polluted rivers in Mexico and to off-shore oil extraction platforms. We found a significant correlation between the community composition and abundance, implying that the overall abundance is defined by the community structure, perhaps as a result of competition. Additionally, our results indicated that there is no relationship between the grain size and the biodiversity observed.

Molecular inferences of three loci within a phylogenetic framework of a subset of the Pannariaceae confirm that the genus Kroswia is nested within the genus Fuscopannaria. The formal combination of the type species of Kroswia into Fuscopannaria is therefore made here, and Kroswia is reduced into synonymy with the latter genus.