Acarospora brodoana K. Knudsen, Kocourk. & M. Westb. is described from the San Bernardino Mountains in southern California. A black hypothecium distinguishes it from other species with a carbonized epihymenium. Sarcogyne albothallina K. Knudsen, Wheeler & M. Westb. is described from the Missouri Breaks in Montana. A white non-farinose thallus and production of 4-O-methylhiascic acid distinguishes it from other species with a carbonized epihymenium. Both species would previously have been placed in Polysporina. The current reported diversity of Acarosporaceae in North America north of Mexico is 93 species.

Two new species of Bryoria are described based on morphology, chemistry and molecular phylogeny (ITS and Mcm7). Both species belong in section Bryoria, which was resolved as a polyphyletic group in the ITS+Mcm7 phylogeny. Bryoria alaskana belongs to a clade restricted to South-East Asia and north-west North America, and is so far known from south-east Alaska and the Sino-Himalayan Mountains. This highly variable species is most reliably recognized by its pendent, esorediate thallus, its production of fumarprotocetraric acid, and the combination of isotomic branching, abundant, whitish, predominantly fusiform pseudocyphellae, and sparse, short perpendicular side branches. Black emorient patches are lacking. Bryoria irwinii is endemic to north-west North America and is closely related to B. araucana from South America, B. poeltii from South-East Asia, as well as B. nadvornikiana and B. trichodes, both widely distributed in the Northern Hemisphere. It is a subpendent, esorediate species recognized by its predominantly anisotomic branching, olivaceous hue, black emorient patches, conspicuous pale brownish, fusiform pseudocyphellae, and numerous perpendicular, more or less basally constricted, side branches.

Rhizocarpon quinonum McCune, Timdal & Bendiksby is described as a new species from two sites in Katmai National Park, south-western Alaska, in a suboceanic climate near the limit of trees on the Alaska Peninsula. Most similar in external appearance to R. arctogenum, R. bolanderi, R. leptolepis, and R. rittokense, the species is distinguished by the presence of an anthraquinone as a major substance. Mature apothecia are unknown, but ITS sequences are most similar to those of R. copelandii and R. jemtlandicum, although those species differ greatly in morphology from R. quinonum.

Lecanora inaurata, a corticolous member of the L. subfusca group, is described as new to science. This species is characterized by typically epruinose, reddish brown apothecial discs, a chlarotera-type epihymenium, pulicaris-type amphithecium, and chloroatranorin and zeorin as major constituents, often with accessory calycin in the thalline margins of the apothecia, imparting a distinctive yellow halo appearance when present in sufficient concentrations. Lecanora inaurata occurs in open hardwood-dominated woodlands of the Edwards Plateau and grasslands of the southern Great Plains in Oklahoma and Texas.

A revision of the North American members of the Leptogium saturninum group (i.e. species with long lower-surface hairs, isidia, and usually smooth upper surface) is presented based on molecular phylogenetic analyses of mtSSU and nrITS sequence data, together with an extensive morphological study. Three species supported by both molecular and morphological characteristics are recognized: L. acadiense sp. nov. (distinguished by granular saturninum-type isidia, medulla composed of irregularly arranged or perpendicular hyphae), L. cookii sp. nov. (distinguished by cylindrical saturninum-type isidia) and L. hirsutum (distinguished by hirsutum-type isidia and medulla composed of loosely intertwined hyphae). One species supported by morphological characteristics, but for which no molecular data could be generated, is also recognized: L. compactum sp. nov. (distinguished by hirsutum-type isidia and medulla composed of tightly packed hyphae). Finally, L. saturninum (distinguished by granular saturninum-type isidia and medulla composed of perpendicular and parallel hyphae) is supported by morphological characteristics but molecular data from geographically diverse populations, including those near the type locality, indicate that the morphologically defined species is paraphyletic. Leptogium burnetiae is excluded from North American based on morphological study of the type. The species are described and illustrated in detail, and are distinguished morphologically by their isidium development, morphology of mature isidia, and pattern of hyphae in the medulla in transverse sections near lobe margins. A key to the members of the L. saturninum group and related species is also presented.

Western North America is the global centre of diversity for Letharia, a distinctive and cryptically diverse genus of lichenized fungi belonging to the Parmeliaceae. The genus is characterized by a shrubby, fruticose habit and presence of vulpinic acid. Previous studies using multiple fungal nuclear loci revealed the existence of two distinct species-level lineages within the traditional concept of L. vulpina and four such lineages within L. columbiana. Here we use molecular sequence data in an attempt to settle long-standing taxonomic issues in the genus. Our results confirm the widespread existence within L. vulpina s. lat. of two distinct species-level groups, each forming a mutually exclusive partnership with a separate algal clade within Trebouxia jamesii s. lat. Accordingly, we formally describe the segregate species L. lupina sp. nov. Our results also support the evolutionary independence of four candidate species previously circumscribed from L. columbiana s. lat. One of these lineages, L. ‘gracilis’, has already received species recognition as L. gracilis, while a second, L. ‘lucida’, is epitypified here against L. columbiana s. str. Based on results from species delimitation analyses under the multispecies coalescent model, the two remaining lineages, L. ‘barbata’ and L. ‘rugosa’, also warrant formal taxonomic recognition; however, we refrain from describing these species pending additional studies of diagnostic characters, ecological preference, and distributions.

Two species of Catinaria with an unusual hepaticolous (i.e. growing on liverworts) lifestyle are described as new to science. Catinaria brodoana is described from species of Cheilolejeunea sect. Leucolejeunea (Lejeuneaceae) growing in south-eastern North America. Catinaria radulae is described from Radula flavifolia (Radulaceae) growing in the Cape Horn Archipelago of southernmost Chile, South America. The species are compared with the type of Catinaria (C. atropurpurea). In addition to occurring on hepatics, C. brodoana is characterized by its cellular exciple, warted ascospores and thallus composed of goniocysts, while C. radulae is characterized by its exciple of radiating hyphae, warted ascospores and absence of a lichenized thallus.

A new cyanolichen, Peltigera islandica sp. nov. in the section Peltigera (‘P. canina group’) is described from Iceland. This species is similar in general appearance to P. rufescens and P. membranacea, but may be recognized by its downturned lobe tips and narrow lobes, respectively. Most thalli are bright emerald green in colour when moist, although a dark khaki green colourmorph is also documented. Monophyly of P. islandica s. lat. (i.e. including P. sp. A sensu O’Brien et al., from Canada) is significantly supported based on ITS sequences and corroborated by molecular synapomorphy (absence of the ITS1 hypervariable region). Analysis of the rbcLX locus indicates the cyanobiont of P. islandica (Nostoc sp.) comprises strains belonging to a pool of Icelandic genotypes, some of which are present in other Peltigera species, including P. “neorufescens”, another taxon new to Iceland collected during this study. Association with photobionts that are shared by other local species suggests P. islandica may be well established in Iceland, but a review of herbarium collections as well as broader field surveys are needed to better characterize its geographical distribution.

The genus Rinodina (Physciaceae), with approximately 300 species, has been subject to few phylogenetic studies. Consequently taxonomic hypotheses in Rinodina are largely reliant on phenotypic data, while hypotheses incorporating DNA dependent methods remain to be tested. Here we investigate Rinodina degeliana/R. subparieta and the Rinodina mniaraea group, which previously have not been subjected to comprehensive molecular and phenotypic studies. We conducted detailed morphological, anatomical, chemical, molecular phylogenetic and species delimitation studies including 24 newly sequenced specimens. We propose that Rinodina degeliana and R. subparieta are conspecific and that chemical morphs within the R. mniaraea group should be recognized as distinct species. We also propose the placement of the recently described genus Oxnerella in Physciaceae.

Three new species of Diploicia are described from the Galapagos Islands and a fourth, D. glebosa, is transferred from Pyxine; all four are considered endemic to the archipelago. In order to accommodate these species, the generic concept of Diploicia has been emended. Two of the species are sterile; D. leproidica is placodioid-leproid, where the thalli derive from pseudocorticate granules aggregating into small, placodioid rosettes with distinctly lobate margins. The second sterile species, D. squamulosa, forms scattered squamules that eventually aggregate into small, placodioid rosettes. The two fertile species, D. glebosa, with an olivaceous to beige, smooth, epruinose upper surface, and D. neotropica, with a white to grey-white, roughened, pruinose upper surface, form larger thalli typical of Diploicia, have apothecia that are initially lecideine, but are soon engulfed and hidden by a thick thalline margin. Anatomically the proper exciple remains visible for a considerable part of the ontogeny, although it eventually becomes almost completely reduced to a few pigmented or almost hyaline hyphae. This transition from lecideine to lecanorine apothecia is similar to the physciaeformis-type ontogeny observed in some Pyxine species. Several species currently accommodated in Buellia s. lat. with diploicin and effigurate thalli that lack distinctly lobate margins are discussed and the Socotran endemic Physcia endopyxinea is transferred into Diploicia.

In our ongoing study of the genus Cladonia, we have encountered several specimens that have proved to represent undescribed species. Four of them are described here as new. Cladonia camerunensis (Cameroon) resembles C. didyma (Fée) Vain., but the former has a coarsely granular surface and a melanotic podetial base; C. compressa (Bolivia) is distinguished by a dominant primary thallus and deeply divided and phyllopodiate podetia; C. longisquama (Seychelles) has well-developed squamules and contains barbatic acid; C. vescula (Bolivia, Peru) differs from C. peziziformis (With.) J. Laundon by an ecorticate podetial surface and the production of homosekikaic acid. The names C. aspera Ahti & Kashiw. and C. crinita (Delise ex Pers.) Ahti are shown to be illegitimate later homonyms and are replaced by the names C. asperula and C. perfoliata, respectively. The neglected name C. botryoides (Tuck.) Vain. is shown to be a synonym of C. squamosa. Another overlooked name, C. crinita Bertol., is shown to be the earliest name for C. evansii, but we propose to retain the latter through conservation. The typification of C. beaumontii Tuck. is amended. Cladonia conspicua is reinstated on the basis of new data. New range extensions in Canada and the United States are given for the poorly documented species C. oricola.

The results of the first molecular phylogenetic study of Pseudephebe are presented; a three-locus phylogeny. The genus is confirmed as monophyletic within the alectorioid clade of Parmeliaceae. Two major clades were recovered, which can be assigned to the two traditional taxa, P. minuscula and P. pubescens, with modifications of the species delimitation, especially the variable P. minuscula. These species are cryptic and cannot be confidently distinguished morphologically due to phenotypic convergence. Therefore, the use of P. pubescens aggr. is recommended for samples not molecularly analyzed. Contrary to previous studies, specimens of both species might have indistinct pseudocyphellae and also contain lichen substances; norstictic acid was detected in c. 60% of specimens tested. An SSU 1516 Group I intron is usually present in P. minuscula but always absent in P. pubescens. The species-level nomenclature is summarized and sequenced reference specimens (RefSpec) for both Pseudephebe species are selected. Sequences from Bryoria mariensis established that this name was a synonym of P. minuscula.

The identity and phylogenetic placement of photobionts associated with two lichen-forming fungi, Umbilicaria spodochroa and Lasallia pustulata were examined. These lichens commonly grow together in high abundance on coastal cliffs in Norway, Sweden and Finland. The mycobiont of U. spodochroa reproduces sexually through ascospores, and must find a suitable algal partner in the environment to re-establish the lichen symbiosis. Lasallia pustulata reproduces mainly vegetatively using symbiotic propagules (isidia) containing both symbiotic partners (photobiont and mycobiont). Based on DNA sequences of the internal transcribed spacer region (ITS) we detected seven haplotypes of the green-algal genus Trebouxia in 19 pairs of adjacent thalli of U. spodochroa and L. pustulata from five coastal localities in Norway. As expected, U. spodochroa associated with a higher diversity of photobionts (seven haplotypes) than the mostly asexually reproducing L. pustulata (four haplotypes). The latter was associated with the same haplotype in 15 of the 19 thalli sampled. Nine of the lichen pairs examined share the same algal haplotype, supporting the hypothesis that the mycobiont of U. spodochroa might associate with the photobiont ‘pirated’ from the abundant isidia produced by L. pustulata that are often scattered on the cliff surfaces. Up to six haplotypes of Trebouxia were found within a single sampling site, indicating a low level of specificity of both mycobionts for their algal partner. Most photobiont strains associated with species of Umbilicaria and Lasallia, including samples from this study, represent phylogenetically closely related taxa of Trebouxia grouped within a small number of main clades (Trebouxia sp., T. simplex/T. jamesii, and T. incrustata+T. gigantea). Three of the photobiont haplotypes were found only in U. spodochroa thalli.

Classical hypotheses in lichenology predict pairs of species in which sexual lineages are ancestral and long-lived evolutionarily and that these give rise to derived, evolutionarily transient asexual lineages. Extensive phylogenetic information generated over the last 20 years regarding relationships within and among various groups of lichens makes possible an investigation of polarity and lability in reproductive mode across diverse clades. To test the long-held hypothesis of asexual reproduction as an evolutionary dead end in lichens, existing phylogenetic data from 23 studies were utilized to reconstruct gains and losses of sexual and asexual reproduction in a model-based statistical framework. Summed across all studies, between 26–44 origins of asexual reproduction from sexual ancestors (forward transitions) and 14–25 origins of sexual reproduction from asexual ancestors (reverse transitions) were identified. However, the higher number of gains of asexual reproduction was concentrated in a relatively low number of clades (e.g. Dirina). The greater number of forward compared to reverse transitions is consistent with dogma in both lichenology and evolutionary biology, but nonetheless this study documents numerous reverse transitions, suggesting that asexual lineages represent a source for evolutionary innovation.

Wapusk National Park is part of the Hudson Bay Lowlands in Manitoba and covers 11 475 km2. Lichen surveys were initiated in 2002 but none have reported all species incorporating broad habitat types or a baseline on which to make management decisions. The objectives of this study were: 1) to determine species diversity, including species richness and evenness of the lichens present; 2) to explore species distributions; and 3) to compare lichen growth form and substratum relationships among physiographic regions. Fifty-six locations in four habitat types (physiographic regions: open coastal beach ridge, forested coastal beach ridge, boreal transition forest, and peat plateau bog) and three burned locations were visited over nine years and specimens were collected at each location. A total of 276 species and subspecies were collected. One species is new to Canada (Buellia uberior Anzi) and ten species are new to Manitoba. Species diversity, evenness, and richness were highest in the coastal beach ridge. The open coastal beach ridge, boreal transition forest, and peat plateau bogs formed separate clusters in the non-metric multidimensional scaling (NMS) but the forested coastal beach ridge overlapped with the open coastal beach ridge. Unique species in each region may serve as indicators to monitor long-term changes. While the coastal beach ridge facilitates travel along the coast, it also represents the region with the highest need for intervention to conserve species diversity.

The fragmented ecosystems along the Niagara Escarpment World Biosphere Reserve provide important habitats for biota including lichens. Nonetheless, the Reserve is disturbed by dense human populations and associated air pollution. Here we investigated patterns of lichen diversity within urban and rural sites at three different locations (Niagara, Hamilton, and Owen Sound) along the Niagara Escarpment in Ontario, Canada. Our results indicate that both lichen species richness and community composition are negatively correlated with increasing human population density and air pollution. However, our quantitative analysis of community composition using canonical correspondence analysis (CCA) indicates that human population density and air pollution is more independent than might be assumed. The CCA analysis suggests that the strongest environmental gradient (CCA1) associated with lichen community composition includes regional pollution load and climatic variables; the second gradient (CCA2) is associated with local pollution load and human population density factors. These results increase the knowledge of lichen biodiversity for the Niagara Escarpment and urban and rural fragmented ecosystems as well as along gradients of human population density and air pollution; they suggest a differential influence of regional and local pollution loads and population density factors. This study provides baseline knowledge for further research and conservation initiatives along the Niagara Escarpment World Biosphere Reserve.