Lichens are widely acknowledged to be a key component of high latitude ecosystems. However, the time investment needed for full inventories and the lack of taxonomic identification resources for crustose lichen and lichenicolous fungal diversity have hampered efforts to fully gauge the depth of species richness in these ecosystems. Using a combination of classical field inventory and extensive deployment of chemical and molecular analysis, we assessed the diversity of lichens and associated fungi in Glacier Bay National Park, Alaska (USA), a mixed landscape of coastal boreal rainforest and early successional low elevation habitats deglaciated after the Little Ice Age. We collected nearly 5000 specimens and found a total of 947 taxa, including 831 taxa of lichen-forming and 96 taxa of lichenicolous fungi together with 20 taxa of saprotrophic fungi typically included in lichen studies. A total of 98 species (10.3% of those detected) could not be assigned to known species and of those, two genera and 27 species are described here as new to science: Atrophysma cyanomelanos gen. et sp. nov., Bacidina circumpulla, Biatora marmorea, Carneothele sphagnicola gen. et sp. nov., Cirrenalia lichenicola, Corticifraga nephromatis, Fuscidea muskeg, Fuscopannaria dillmaniae, Halecania athallina, Hydropunctaria alaskana, Lambiella aliphatica, Lecania hydrophobica, Lecanora viridipruinosa, Lecidea griseomarginata, L. streveleri, Miriquidica gyrizans, Niesslia peltigerae, Ochrolechia cooperi, Placynthium glaciale, Porpidia seakensis, Rhizocarpon haidense, Sagiolechia phaeospora, Sclerococcum fissurinae, Spilonema maritimum, Thelocarpon immersum, Toensbergia blastidiata and Xenonectriella nephromatis. An additional 71 ‘known unknown’ species are cursorily described. Four new combinations are made: Lepra subvelata (G. K. Merr.) T. Sprib., Ochrolechia minuta (Degel.) T. Sprib., Steineropsis laceratula (Hue) T. Sprib. & Ekman and Toensbergia geminipara (Th. Fr.) T. Sprib. & Resl. Thirty-eight taxa are new to North America and 93 additional taxa new to Alaska. We use four to eight DNA loci to validate the placement of ten of the new species in the orders Baeomycetales, Ostropales, Lecanorales, Peltigerales, Pertusariales and the broader class Lecanoromycetes with maximum likelihood analyses. We present a total of 280 new fungal DNA sequences. The lichen inventory from Glacier Bay National Park represents the second largest number of lichens and associated fungi documented from an area of comparable size and the largest to date in North America. Coming from almost 60°N, these results again underline the potential for high lichen diversity in high latitude ecosystems.

The identification of mycocalicioid species continues to be based on morphological and chemical characters, even though molecular data and substratum preferences can provide many important insights into specific problems associated with species delimitation and other taxonomic challenges. Our results reinforce the usefulness of many morphological and chemical characteristics and reveal several new features that can be used for both species delimitation and identification. Given the fact that mycocalicioid species can rarely be distinguished by just a single character, combinations of different chemical and morphological characteristics must be used. Additional characteristics must also be sought, including those that have previously been overlooked or still need to be discovered. As a result of this search, we introduce a new term, pseudohemiamyloid, for a reversible, KOH resistant/enhanced reaction in Lugol's solution.

A new species of Synarthonia, S. leproidica, is described from Luxembourg. Phylogenetic analyses of mtSSU and RPB2 sequences were used to determine the generic affiliation of this sterile species. Synarthonia leproidica differs from all other species of the genus by the combination of a leproid thallus and the production of psoromic acid. It is the sister species to S. muriformis in our phylogenetic analyses. The discovery of the new species suggests that other strictly sorediate lichen species might have been overlooked in Europe, even in intensely explored countries such as Luxembourg. Phylogenetic analyses further confirm the placement of Reichlingia anombrophila in the genus Reichlingia and of Synarthonia astroidestera in the genus Synarthonia. Arthonia atlantica is transferred to the genus Reichlingia as R. dendritica.

The algicolous and lichenicolous species Psammina filamentosa is described from the Netherlands and the UK, and is characterized by long (generally over 50 μm) and somewhat tapered conidial arms. Psammina filamentosa is compared with other Psammina specimens found in the same habitat, growing on algae or lichens on the dry side of trees and stones. Psammina filamentosa, P. inflata and P. stipitata differ in the dimensions of their conidial arms. Psammina simplex, however, may be a synonym of P. stipitata, and a DNA study is needed to determine whether it is a distinct species or developing material of P. stipitata. Psammina inflata is also reported as new for the Netherlands. A new worldwide key to the 10 species of Psammina currently known is provided, including three species described from plant material.

The new combination Ocellomma rediuntum (Stizenb. ex Hasse) Kantvilas, Gueidan & Tehler is proposed, supported by morphological, anatomical and molecular data. Hitherto known only from the Californian coast, this species is here recorded for Kangaroo Island (South Australia), Victoria and Tasmania. It is described and illustrated from Australian collections. The ecology of the species and its remarkable distribution are discussed.

The new species Alyxoria sierramadrensis is described from Mexico where it inhabits limestone rocks. The lichen developing from this fungus is characterized by a placodioid to subfoliose thallus with a white pruinose surface; rounded to shortly elongated ascomata with a black epruinose margin and a widely exposed, white pruinose hymenial disc; hyaline, 3-septate ascospores, 17–25 × 7–9 μm; the presence of anthraquinones rendering the medulla orange. Phylogenetic analyses of nuLSU, mtSSU and RPB2 sequences place this species in the genus Alyxoria (Lecanographaceae). This generic affiliation is surprising because all known Alyxoria species have a crustose thallus. Lecanographaceae mainly includes species without a thallus (lichenicolous taxa) or with a thin crustose thallus, the only exception being Simonyella variegata with a fruticose thallus. The new species belongs to the Alyxoria ochrocheila subgroup, which includes lichens also frequently known to have anthraquinones, white pruinose hymenial discs and 3-septate ascospores. Phylogenetic analyses further determined the systematic position of the monotypic genus Phoebus. This genus, considered as an Arthoniales of uncertain family affiliation, is shown to belong to the Lecanographaceae. With its placodioid thallus, it is another example of a lichenized fungus with a deviating morphology in thallus structure for the family, increasing the number of remarkable cases of parallel evolution of lichen growth forms within the Arthoniales. Phoebus hydrophobius is newly recorded for Mexico.

Porina collina Orange, Palice & Klepsland is described as new from siliceous rocks in the Czech Republic, Great Britain and Norway. The thallus produces isidioid propagules which resemble those in P. rosei, P. hibernica and P. pseudohibernica, but which are more fragile and poorly-defined, and almost ecorticate; the perithecial wall is dark purplish brown and the ascospores are 3-septate. Sequences of the mitochondrial ribosomal DNA suggest that the new species belongs in the Porina byssophila clade.

Since the advent of molecular taxonomy, numerous lichen-forming fungi with homoiomerous thalli initially classified in the family Collemataceae Zenker have been transferred to other families, highlighting the extent of morphological convergence within Lecanoromycetes O. E. Erikss. & Winka. While the higher level classification of these fungi might be clarified by such transfers, numerous specific and generic classifications remain to be addressed. We examined the relationships within the broadly circumscribed genus Arctomia Th. Fr., which has been the recipient of several transfers from Collemataceae. We demonstrated that Arctomia insignis (P. M. Jørg. & Tønsberg) Ertz does not belong to Arctomia s. str. but forms a strong monophyletic group with Gabura fascicularis (L.) P. M. Jørg. We also confirmed that Arctomia borbonica Magain & Sérus. and the closely related Arctomia insignis represent two species. We formally transferred A. insignis and A. borbonica to the genus Gabura Adans. and introduced two new combinations: Gabura insignis and Gabura borbonica. We reported Gabura insignis from Europe (Scotland and Ireland) for the first time. While material from Europe and North America is genetically almost identical, specimens from Madagascar, South Africa and Reunion Island belong to three distinct phylogenetic lineages, all of which are present in the latter area and may represent distinct species. In its current circumscription, the genus Gabura may contain up to six species, whereas Arctomia s. str. includes only two species (A. delicatula Th. Fr. and A. teretiuscula P. M. Jørg.). The Gabura insignis group is shown to have an unexpectedly large, subcosmopolitan distribution. With the extended sampling from Arctomiaceae Th. Fr., the placement of Steinera sorediata P. James & Henssen in the genus Steinera Zahlbr. is confirmed and the presence of a new Steinera species from Chile is highlighted.

The new species Psoroma capense and P. esterhuyseniae are described from four alpine localities in the Western Cape Province of South Africa and are the only known Psoroma species from Africa. The specimens were all collected from moist sites near watercourses, on cool and mostly south-facing cliffs. Psoroma capense resembles P. tenue in gross morphology but differs in the ascending thallus squamules, lack of secondary compounds and short-ellipsoid to ovoid ascospores. However, a phylogenetic analysis involving the markers ITS, nucLSU, mtSSU and Mcm7, comparing the only recent collection of P. capense with previously published sequences, shows that it belongs to the P. hypnorum lineage, with no known, closely related species. Psoroma esterhuyseniae resembles P. hypnorum but has subglobose to short-ellipsoid ascospores without apical perispore extensions. The two species are thought to have evolved from one or two long-distance dispersal events during the Pleistocene.

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.

Two Tasmanian species of the genus Cresponea are treated: C. graemeannae Kantvilas sp. nov., characterized by a very thin, saxicolous thallus, apothecia with a thick, radially fissured margin, thinly pruinose disc, hypothecium inspersed with oil droplets, and 5–9-septate ascospores, 25–40 × 6–8 μm; and C. subpremnea (Kantvilas & Vĕzda) Kantvilas comb. nov. The latter has ascospores 30–58 × 4.5–7 μm, which distinguish it from the related C. plurilocularis (Nyl.) Egea & Torrente (ascospores 27–45 × 6–8 μm). The taxa are illustrated, discussed and compared. Cresponea litoralis Elix, based on an Australian type, is considered a synonym of Bactrospora myriadea (Fée) Egea & Torrente. A key to the species of Cresponea reported from Australia is presented.

Basidiolichens are generally poorly researched because of the very small number of species and their restriction to special niches. Lichenomphalia basidiolichens grow in considerable quantities in arctic and alpine habitats but they are inadequately studied in these habitats in Mediterranean areas. Based on morphological and phylogenetic analyses, we identified the different symbionts of L. meridionalis, collected in localities in Spain at altitudes ranging from 533 to 2200 m above sea level. The present study provides the first molecular data available for L. meridionalis. We found that a microindel of six bp within the nrITS2 could help to discriminate L. meridionalis from other species of the genus. Molecular analyses revealed the existence of two different green algal strains, both belonging to Coccomyxa subellipsoidea, a species shared with other Lichenomphalia lichens. Notably, the two chlorobiont strains associated with L. meridionalis were differentially distributed according to altitude, and samples having one of the two strains consistently also included cyanobacteria.

The identity of Lecanora ecorticata has been uncertain due to conflicting reports of the presence of zeorin and the loss of the holotype. Phylogenetic analysis suggests that the species probably belongs in Ramalinaceae, where it is the first leprose species reported. Zeorin was found to be absent in recently collected material of L. ecorticata, including specimens from the type locality, and the report of zeorin in the lost holotype is considered to be due to contamination. A new genus, Lithocalla, is erected to accommodate L. ecorticata and a second closely related species, that occurs in the Falkland Islands, is newly combined as Lithocalla malouina. A lectotype is selected for L. ecorticata. Lithocalla is characterized by a leprose thallus containing usnic acid with fatty acids and terpenoids, but no zeorin; ascomata and conidiomata are unknown.

Lichens of the Ramalina siliquosa complex dominate seashore cliffs in Europe and South-East Asia, but their taxonomy has been vigorously debated for over a century. On many cliffs, they exhibit a bewildering zonation of chemotypes that resembles the classic zonation of organisms that occupy the littoral zone below. Do the chemotypes represent separate species, or infraspecific variation? To better understand the systematics of this group, sequences from four genetic loci (ITS, IGS, RPB1 and RPB2) were obtained for 59 samples from Denmark, France, Iceland, Norway, UK, Japan and Korea, including all major chemotypes. Maximum likelihood analysis of these sequences, together with sequences from 36 other Ramalina species, reveals that the complex comprises two distinct phylogenetic lineages, each including multiple chemotypes. These two putative species-level lineages correspond to the currently accepted taxa R. cuspidata and R. siliquosa. There is no evidence that these two taxa are phylogenetic sister species. Consequently, the explanation of this chemotype complex as an example of ‘sibling speciation’ is rejected. Specimens traditionally called ‘R. siliquosa’ from South-East Asia form a third clade, identified here as R. semicuspidata, with an additional, divaricatic acid chemotype. Other results include a robustly supported clade of Ramalina species that produce medullary depsides and depsidones; this clade includes another well-supported clade of south-eastern United States coastal plain and tropical Ramalina species. By contrast, large, strap-shaped Ramalina species that lack medullary depsides and depsidones occur in separate lineages. In addition, close relationships between the following groups of species are indicated: R. farinacea with R. subfarinacea; R. fraxinea with R. leptocarpha, R. menziesii and R. subleptocarpha; R. sinensis with R. unifolia. Furthermore, a new, variolaric acid-only chemotype is reported for R. farinacea, and a new, acid-deficient chemotype is reported for a more broadly circumscribed R. culbersoniorum.

The circumscription of the lichenized ascomycete genus Icmadophila Trevis. in the family Icmadophilaceae Triebel was investigated. Sequences of the internal transcribed spacer (ITS) region and large subunit of nuclear ribosomal DNA (nuLSU) were generated for the five Icmadophila species and additional members of Icmadophilaceae from the genera Dibaeis, Endocena, Knightiella, Siphula, Siphulella and Thamnolia. Phylogenetic analyses indicate that three Icmadophila species are closely related: the type, I. ericetorum (L.) Zahlbr., which is widespread in Eurasia and North America, I. aversa (Nyl.) Rambold & Hertel from Central and South America, and I. japonica (Zahlbr.) Rambold & Hertel, which is restricted to Far East Russia and Japan. The genus Knightiella Müll. Arg. is reinstated to accommodate I. splachnirima (Hook.f. & Taylor) D. J. Galloway emend. L. Ludw., which occurs in New Zealand and Australia. Two further species of Knightiella, K. eucalypti (Kantvilas) Kantvilas and K. queenslandica Kantvilas, are found to be unrelated to K. splachnirima, and are accommodated in two newly described genera, Knightiellastrum and Siphulopsis respectively. Knightiellastrum L. Ludw. & Kantvilas is characterized by a squamulose, erhizinate, whitish to pale grey thallus with a green, coccoid photobiont and by containing thamnolic acid. Siphulopsis Kantvilas & A. R. Nilsen is similarly characterized by an erhizinate, whitish to pale grey thallus, with a green, coccoid photobiont and containing thamnolic acid, but is instead fruticose. This study reveals considerable diversity within Australasian Icmadophilaceae; ongoing work in the Southern Hemisphere and tropical regions may reveal additional species in this family and clarify the relationships of these newly described genera.

New collections are reported of the monospecific genus Polypyrenula, an apparently extinct and doubtfully lichenized fungus, typically classified in the Pyrenulaceae. Anatomical studies reveal that it is facultatively lichenized. The structure of its hamathecium suggests affinities with Dothideomycetes rather than Eurotiomycetes. Molecular analysis using nuLSU and mtSSU markers demonstrates for the first time its inclusion in Trypetheliaceae, outside the core genera as part of the early diverging lineages in this family. The known distribution of Polypyrenula is extended to Mexico and South America, new information on its phorophyte associations is provided, and the name Polypyrenula sexlocularis is reinstated as the correct name for this species.