Aptrootia khaoyaiensis Polyiam & Lücking is described as new to science from dry dipterocarp forest in central Thailand, based on morphological assessment and sequence data of the mitochondrial small subunit (mtSSU). The new species is characterized by a corticolous habit, a corticate thallus, ascomata typically immersed in the thallus, with a brown to blackish ostiolar region, an inspersed hamathecium, and dark brown, muriform ascospores occurring 1–2 per ascus. Phylogenetic analyses support placement of the new species in Aptrootia; it is morphologically close to A. elatior but differs in the smaller ascospores and the inspersed hamathecium.

Persepolis, a UNESCO World Heritage Site in south-western Iran, dates back to more than 2500 years ago, and is colonized by a great diversity of lichen-forming fungi. A survey of the lichen-forming fungi revealed a species abundant in different areas of the cultural site, which turned out to be a new species of the genus Circinaria. The new species, Circinaria persepolitana, is introduced and described on the basis of morphological and molecular data. Circinaria persepolitana is characterized by having a crustose thallus, rimose to areolate, usually with bullate areoles, with an olive green to olive-brown surface and angular to elongate areoles in the marginal zone. Phylogenetic analyses including other species of the genus showed that the new species is phylogenetically close to C. mansourii, C. ochracea and C. reptans. We propose a new combination of Circinaria reptans (Looman) Sohrabi, Owe-Larsson & Paukov. The bioweathering capacity of the new species was also analyzed by scanning electron microscopy, examining the interface between the lichen thallus and the lithic substratum to assess its potential threat to the conservation of heritage surfaces. We found this species to be a potential biodeteriogenic agent, as thalli were closely attached to the lithic substratum and biogeophysical and biogeochemical changes at the rock surface could be associated with the colonization.

Cladonia sandstedei forms cushion-shaped lichens that colonize open environments and is distributed throughout the Caribbean and the south-eastern United States. It co-occurs in parts of its range with C. subtenuis, a morphologically similar taxon that is distinguished from the former by the presence of usnic acid. Preliminary phylogenetic analysis with the RPB2 and TEF-1α loci revealed that these taxa were closely related, but relationships were inconsistent among markers. Here, we combined phylogenetic and population genomic analyses based on RADseq data to clarify the evolutionary relationships and phylogeography of these taxa. Both approaches indicate that the taxa cannot be separated based on secondary metabolites, as previously proposed, but instead form a complex composed of several lineages, largely unrelated to chemistry but with a strong geographical structure in their genetic variation. Continental populations formerly separated under the names C. sandstedei and C. subtenuis were closely related to each other. A similar pattern was observed in the Jamaican counterparts of these taxa, suggesting homoplasy of secondary chemistry. Discriminant Analysis of Principal Components (DAPC) hinted at potential conspecificity between populations in Cuba and Puerto Rico on one hand, and between Jamaica and the continental US on the other; however, phylogenetic analysis and other population-level analyses (PCA and fineRADstructure) suggested that both insular and continental populations were more likely to be reproductively isolated from each other. Based on this, we propose to recognize only one species for the entire complex, under the older name C. sandstedei, with the four spatially structured clades as subspecies: C. sandstedei subsp. sandstedei (restricted to Jamaica) and C. sandstedei subsp. subtenuis comb. nov. (restricted to continental North America) exhibit several chemosyndromes variably containing usnic acid and/or atranorin. The two additional subspecies described here as new, C. sandstedei subsp. cubana and C. sandstedei subsp. landroniana, exhibit the atranorin chemosyndrome and are restricted to Cuba and Puerto Rico, respectively. Our work reaffirms the power of combining RADseq-based phylogenetics and population genetics to disentangle taxonomic and evolutionary histories in poorly understood, closely related and phenotypically similar lichen-forming fungal species.

Sticta canariensis is a lichen which is rare in all parts of its range in Atlantic Europe and Macaronesia, where it occurs in laurisilva forests, a habitat highly threatened by global change. Thus, this species is of high priority for inclusion in conservation programmes where genetic diversity should be considered. We have established new microsatellite loci and generated a dataset that demonstrates the genetic diversity of the lichen-forming fungus S. canariensis from eight locations across its disjunct range, in Macaronesia, Norway and England. We genotyped 25 microsatellite loci for 65 specimens and detected five genetic clusters which resemble major geographical divisions, specifically among the Macaronesian archipelagos. The total number of observed alleles ranged from 2 to 22. These are the first microsatellite markers developed for S. canariensis and they will be useful for population genetic studies and for conservation assessments.

We investigated the influence of availability as well as type of organic substrate on the growth of the cyanolichen Peltigera membranacea. A total of 145 lichen lobes were grown in a plant growth chamber for 28 days. Of these, 73 were kept in permanent darkness and another 72 were exposed to a diurnal light-dark cycle. A third of the lobes from both treatments were grown on pulverized leaf litter, the second third on pulverized bryophytes, and the remainder were grown without an organic substrate to serve as a control group. Growth was quantified via relative growth rate, relative thallus area growth rate, and changes in specific thallus mass. The lobes kept in a diurnal light-dark cycle showed higher growth rates than those kept in darkness, as is expected for an organism that obtains its carbon from its photoautotrophic symbiosis partner. Furthermore, growth rates were higher in lobes growing on organic substrates. The results show that the availability of an organic substrate positively affects lichen growth in a growth cabinet. Leaf litter led to a higher biomass gain in lichen lobes, whereas area gain was unrelated to substrate type.

While the diversity of foliicolous lichen-forming fungi has been explored in substantial depth, relatively little attention has been paid to their algal symbionts. We studied the unicellular green phycobionts of the lecanoralean lichens Bacidina (Ramalinaceae), Byssoloma, Fellhanera and Tapellaria (Pilocarpaceae) and graphidalean Gyalectidium (Gomphillaceae) from two extratropical foliicolous communities in continental Spain and the Canary Islands. We examined the pyrenoids of algal symbionts within thalli using TEM, and obtained several algal nrSSU and rbcL sequences from whole thalli, and also from cultures isolated from some of these lichens. Pyrenoid structure and molecular sequence data provided support for recognizing Chloroidium (Watanabeales, Trebouxiophyceae) as phycobiont in thalli of Byssoloma subdiscordans and Fellhanera bouteillei (Pilocarpaceae) in both communities. Bacidina apiahica (Ramalinaceae) and Tapellaria epiphylla (Pilocarpaceae) likewise appeared to partner with Chloroidium based on the presence of the same pyrenoid type, although we were able to obtain a phycobiont sequence only from a culture isolate of the latter. These results contrast with those obtained previously from a foliicolous lichen community in southern Florida, which revealed only strains of Heveochlorella (Jaagichlorella) as phycobiont of foliicolous Pilocarpaceae and Gomphillaceae. On the other hand, the pyrenoid we observed in the phycobionts associated with Gyalectidium setiferum and G. minus corresponded to that of Heveochlorella (Jaagichlorella). However, the poor quality of the phycobiont sequence data obtained from G. minus, probably due to the presence of epibiontic algae, could not provide additional perspective on the pyrenoid structure observations. Nonetheless, clear differences in pyrenoid ultrastructure can allow Chloroidium and Heveochlorella phycobionts to be distinguished from each other in TEM. Our results indicate a greater diversity of unicellular green-algal symbionts in foliicolous communities from Spain than previously observed in other geographical areas, and suggest that further studies focused on symbiont pairing in these communities might reveal distinctive and varied patterns of phycobiont preference.

An experiment was conducted on the development of Hypogymnia physodes (L.) Nyl. from soredia to branched lobes near the copper smelter in the Middle Urals 10 years after emission cessation. Soredia were cultivated in fir-spruce forests in heavily polluted and unpolluted areas. In both areas, soredia development was examined on fir bark collected from both the heavily polluted and unpolluted areas. The probability of lobe formation was lower in the polluted area even when soredia were cultivated on bark from the unpolluted area. Bark from the polluted area negatively impacted the success of soredia development, irrespective of the cultivation area. The lowest success of early development occurred when soredia were cultivated on polluted bark in the heavily polluted area, where the already low probability of lobe formation was accompanied by high mortality of the developed lobes. This study underscores the enduring impact of industrial pollution on H. physodes development, highlighting the need for ongoing environmental restoration and monitoring efforts in post-industrial areas to support biodiversity conservation.

The Cladonia cervicornis group comprises lichen-forming fungi characterized by having scyphi with central proliferations. It includes c. 20 species globally. The taxonomy of this group is poorly resolved, with many species not thoroughly disentangled. The focus of this study is the European species in the C. cervicornis group. In order to estimate the phylogenetic relationships of these species, six loci were used: ITS rDNA, IGS rDNA, RPB1, RPB2, ef1α and cox1. Species delimitation methods (ASAP, PTP and GMYC) were used to infer the species boundaries based on four loci, ITS rDNA, IGS rDNA, cox1 and RPB2. A morphological analysis based on multivariate methods was performed to assess the importance of phenotypic differences among the lineages. The phylogenetic reconstructions placed the species of this group in the subclade Cladonia. Five lineages were recovered, corresponding to C. cervicornis, C. macrophyllodes, C. pulvinata, C. verticillata and a new lineage that we describe here, C. teuvoana. Our analyses revealed that Cladonia cineracea, C. stricta and C. trassii are polyphyletic.

Seven new species of Verrucaria are described from Finland: Verrucaria hakulinenii sp. nov., V. juumaensis sp. nov., V. linkolae sp. nov., V. lohjaensis sp. nov., V. norrlinii sp. nov., V. oulankajokiensis sp. nov., and V. vainioi sp. nov. Verrucaria linkolae is also reported from the Czech Republic, Germany and the United Kingdom, V. norrlinii from Norway and V. juumaensis from Canada based on a previously unidentified soil sample. Based on ITS sequences, V. hakulinenii and V. juumaensis probably belong to the Verrucaria hydrophila group whereas V. linkolae, V. norrlinii, V. oulankajokiensis and V. vainioi are closely related to V. hunsrueckensis and V. nodosa. The new species are characterized by a thin brown or green thallus, rather small perithecia and a predominantly thin involucrellum reaching the exciple base level. Verrucaria hakulinenii is characterized by a thin thalline cover of the perithecia, a green thallus and fairly large spores (18–22 × 8–10 μm). Verrucaria juumaensis, V. linkolae, V. norrlinii and V. vainioi are characterized by a predominantly brown thallus, often with goniocyst-like units. Verrucaria linkolae has densely occurring perithecia (100–330 perithecia per cm2) whereas in V. juumaensis, V. norrlinii and V. vainioi perithecia occur more sparsely (40–160 perithecia per cm2). Verrucaria juumaensis and V. vainioi usually have a minute thallus. Verrucaria juumaensis differs from V. vainioi by slightly larger perithecia (0.18–0.27 mm diam.) and longer and wider spores. Verrucaria lohjaensis is characterized by a mosaically dark brown and white, small areolate thallus and conspicuous ostioles. Verrucaria oulankajokiensis has small perithecia that are often thinly covered by thalline tissue and a thallus partly surrounded by dark lines. Most species occur on calcareous rocks, but V. vainioi is restricted to siliceous rocks. Verrucaria linkolae and V. norrlinii are widely distributed both on calcareous, serpentine and siliceous rocks, preferring pebbles. Epiphytic occurrences of V. linkolae and V. norrlinii are confirmed. A key to the new species and species with a similar morphology in Finland is provided.

We present a robust, five-locus phylogeny of the Megasporaceae and, based on this, propose several taxonomic innovations. The new genus Antidea is erected for Aspicilia brucei, which occupies a position near the base of the phylogeny, and the new species Aspicilia indeterminata and A. suavis are described from Montana. We also show that all North American (and some European) records of Aspilidea myrinii are misidentifications with many representing a second species in the genus, differing from A. myrinii by having elevated apothecia and narrower ascospores and for which we make the new combination Aspilidea subadunans. Finally, we make the new combinations Lobothallia determinata and L. peltastictoides, and report the lichenicolous fungus Sagediopsis aspiciliae (on A. subadunans) as new to North America.

Candelariella ahtii Yakovchenko sp. nov. is described based on phenotypic and ITS nrDNA sequence data. The species, occurring on soil in the crevices and cracks of siliceous rocks, is characterized by its squamulose cushion-forming thallus of imbricate, rounded to weakly incised granules/squamules with a greenish yellow to pale yellow pulverulent upper surface, lecanorine apothecia with a plane to somewhat convex ochre-yellow disc and a permanent thick thalline margin, 8-spored asci and ellipsoid to narrowly ellipsoid ascospores with rounded ends, as well as a distribution in Central and North-East Asia. It is similar to Candelariella citrina but differs in having ascospores without attenuated ends and smaller squamules. Candelariella citrina is excluded from the lichen flora of Russia. A worldwide key to all known Candelariella species with 8-spored asci, including 41 names, is provided.