We report on the pore size distribution and water retention of Beacon sandstone from Antarctica that harbours a cryptoendolithic community, predominantly lichens, just below the surface. We measured the pore size distribution, drying time and equilibrium relative humidity of sandstone samples that were colonized by lichens. The incremental pore volume distribution peaks at ~10 μm radius, but ~20% of the pore volume occurs for a radius < 0.02 μm. Water from snowmelt fills ~20% of the total pore volume. It takes ~4–5 days of evaporation to lose 90% of the water. As the rock loses water, the equilibrium relative humidity remains at 99% until an appreciable amount (80–90%) of the pore water is lost, after which the equilibrium relative humidity starts to decrease. The relative humidity remains at > 80% (68 h) long after the water content falls to < 98% (19 h) - the point at which liquid water is estimated no longer to be present. Lichens can remain active in air with high relative humidity (> 80%). Thus, the pore size distribution of the sandstone may play a role in explaining why lichens dominate these sandstones.

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.

To study the physico-chemical activity of lichens on micaceous components of granitic rocks, samples covered by thalli of Parmelia conspersa (Ehrht) Ach. and Aspicilia intermutans (Nyl.) Arn. were collected and examined with Scanning Electron Microscopy (SEM) equipped with a Back Scattered Electron (BSE) detector and an Energy Dispersive Spectroscopy (EDS) microanalytical system. The bio-physical activity of both lichen species leads to a deep alteration of biotite, which results in detachment, separation and exfoliation of biotite plates. Chemically, the bioweathering process of biotite in the lichenmineral contact zone involves considerable depletion of potassium (K) from interlayer positions in biotite and removal of several elements, corresponding to a 9.7% loss in matter. The sequence of the loss of elements is: K+ » Fetot > Ti4+ ≅ Mg2+. There are also some gains in the order: Ca2+ > Na+ » Al3+ > Si4+ attributed to dissolution of co-existing Ca and Na rich minerals. Geochemical mass balance results suggest the transformation of K-rich biotite to scarcely altered biotite interstratified with a biotite-vermiculite intermediate phase in the lichen bioweathered contact zones.

The question of whether clay minerals can be biogenically transformed as a result of lichen activity at the lichen-rock interface remains unresolved. We applied several microscopical and analytical techniques—scanning electron microscopy-back-scattered electron (SEM-BSE), energy dispersive spectroscopy (EDS) and high-resolution transmission electron microscopy (HRTEM)—in an attempt to address this issue. Unaffected granitic biotite and bioweathered material from the granitic biotite and Parmelia conspersa lichen thalli interface were examined using HRTEM after ultrathin sectioning. The n-alkylammonium treatment of ultrathin sections was carried out in order to study the biogenous mineralogical transformation of the biotite. Microsamples proceeding from unaffected biotite zones demonstrated homogenous 10-Å d(001)-value biotite phase. HRTEM images of lattice fringes of samples taken from the lichen-biotite contact zone reveal large areas of both unexpanded (10-A) and randomly and R = 3 distributed expanded (from 14- to 30-Å) layers of phyllosilicates identified as interstratified biotite-vermiculite. Results of artificial biotite weathering (replacement of K by Ca ion) also revealed the biotite-vermiculite phase formation, indicating that K release in biotite is one of the mechanisms responsible for interstratified mineral phase formation. Two parallel processes, physical exfoliation of biotite and inter-layer ionic exchange of K and subsequent vermiculite formation, are the mechanisms for biotite bioweathering induced by lichens.

During a field trip to the highlands of Mount Meru in Tanzania, two Placopsis specimens were collected. Morphological analyses showed a unique combination of characters not observed in any other published taxa within the genus. The specimens are characterized by their circular soralia, not confluent, crater-shaped, with a prominent white margin and coarse granular pinkish central soredia. Considering the morphological, geographical and genetic data, we propose the designation of a new species, Placopsis craterifera Boluda sp. nov.

Seven species of Cliostomum Fr. recorded from Australia are treated. These include the widespread C. griffithii (Sm.) Coppins, the austral C. praepallidum (Müll. Arg.) Kantvilas & Fryday and the Tasmanian endemic C. vezdae Kantvilas, a reinstated name previously subsumed under C. flavidulum Hafellner & Kalb. Three species are described as new: C. latisporum Kantvilas, a corticolous species containing atranorin and gangaleoidin from coastal Tasmania and New South Wales, characterized by pale pink, soon immarginate apothecia, 0.3–0.9 mm wide, non-capitate, unpigmented paraphyses, and relatively wide, 1(–3)-septate ascospores, 9–15 × 4–6 μm; C. litorale Kantvilas, a saxicolous species containing atranorin and confluentic acid, recorded only from Tasmania, with relatively large, usually pale pinkish apothecia, 0.6–1.5 mm wide, non-capitate paraphyses, and 1(–2)-septate ascospores, 9–13 × 4−6 μm; and C. saxatile Kantvilas, a saxicolous species containing atranorin and lecanoric acid, also known only from Tasmania, with dark brown to black apothecia, 0.3–0.5 mm wide, pigmented with Laurocerasi-brown, capitate paraphyses, and 1-septate ascospores, 7–14 × 3–5 μm. The widespread, coastal Australasian species Tylothallia verrucosa (Müll. Arg.) Kantvilas is transferred to Cliostomum, with the additional synonym Catillaria brisbanensis Räsänen. Megalaria variegata (Müll. Arg.) D. J. Galloway, based on a New Zealand type, is a further synonym of Cliostomum griffithii. All species are illustrated and described on the basis of Australian and Tasmanian specimens.

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.

There is still a high diversity of lichen-forming fungi that remains undescribed, especially cryptic lineages at the species level. Integrating morphological, chemical, and DNA sequence data has proved useful in corroborating species descriptions and delimitations. Here we reviewed morphological features, secondary metabolites and the DNA sequences of ITS, mtSSU and nuLSU markers to study the diversity of Xanthoparmelia in southern Africa. A total of 37 species were recorded. Three of these appear undescribed, and we therefore describe them here as new: Xanthoparmelia nimisii, with a sorediate thallus and broad lobes, is well supported as a clade separate from X. annexa; X. pseudochalybaeizans with a white medulla is phylogenetically distinct from the otherwise similar X. chalybaeizans; and X. sipmaniana, well supported as a separate clade from the similar X. hypoprocetrarica. In addition, the separation of Xanthoparmelia capensis and X. tinctina requires further studies.

We present a novel identification tool called PhyloKey, based on the method of morphology-based, phylogenetic binning developed within the software package RAxML. This method takes a reference data set of species for which both molecular and morphological data are available, computes a molecular reference tree, maps the morphological characters on the tree, and computes weights based on their level of consistency versus homoplasy using maximum likelihood (ML) and maximum parsimony (MP). Additional units for which only morphological data are known are then binned onto the reference tree, calculating bootstrap support values for alternative placements. This approach is modified here to work as an identification tool which uses the same character coding approach as interactive keys. However, rather than identifying individual samples through a progressive filtering process when entering or selecting characters, query samples are binned in batch mode to all possible alternative species in the tree, with each placement receiving a bootstrap support adding to 100% for all alternative placements. In addition to the fact that, after scoring a character matrix, a large number of specimens can be identified at once in short time, all possible alternative identifications are immediately apparent and can be evaluated based on their bootstrap support values. We illustrate this approach using the basidiolichen genus Cora, which was recently shown to contain hundreds of species. We also demonstrate how the PhyloKey approach can aid the restudying of herbarium samples, adding further value to these collections and contributing with large quantitative data matrices to ‘non-molecular museomics’. Our analysis showed that PhyloKey identifies species correctly with as low as 50% of the characters sampled, depending on the nature of the reference tree and the character weighting scheme. Overall, a molecular reference tree worked best, but a randomized reference tree gave more consistent results, whereas a morphological reference tree performed less well. Surprisingly, even character weighting gave the best results, followed by parsimony weighting and then maximum likelihood weighting.

Porina is a widely distributed, species-rich genus of crustose, lichen-forming fungi, some with thalline outgrowths that have been recognized as isidia. We studied three taxa with thalli consisting chiefly of ascending isidioid structures occurring on trunks and branches of Taxodium in southwestern Florida, and provide details of their structure with light and electron microscopy. Two of these taxa we describe as new species: P. microcoralloides and P. nanoarbuscula. Genetic sequences (mtSSU) suggest that they are closely related to each other, yet they differ markedly in the size, morphology and anatomical organization of their isidioid branches as well as in the length of their ascospores. In the three Floridian taxa studied, the crustose portion of the thallus is partly endophloeodic and partly superficial, the latter often patchy, evanescent or inconspicuous, and completely lacks the differentiated anatomical organization characteristic of the isidioid structures arising from it. In Porina microcoralloides, the ascendant thallus consists of branched, coralloid inflated structures with phycobiont (Trentepohlia) unicells arranged at the periphery of a loose central medulla. Sparse fungal cells are interspersed and overlie the algal layer in places, but no differentiated cortex is present, leaving phycobiont cells more or less exposed at the surface. In the closely related Porina nanoarbuscula, the isidioid structures are much finer, more densely branched, and composed of a single, central file of roughly spherical Trentepohlia cells surrounded by a jacket of subglobose fungal cells. The ascospores of P. microcoralloides are more than twice the length of those of P. nanoarbuscula. Although thalli of these two Porina species occur in the same habitats and are sometimes found growing alongside each other, phylogenetic analysis of rbcL sequences suggest that they partner with distinct clades of Trentepohlia phycobionts. A third taxon examined, Porina cf. scabrida, is morphologically rather similar to P. microcoralloides, but the ascendant branches are bright yellow-orange, more cylindrical, and corticated by a thin layer of agglutinated fungal hyphae; perithecia were not seen. Analysis of mtSSU sequences places it distant from P. microcoralloides and P. nanoarbuscula phylogenetically. None of the Floridian taxa studied was particularly close to the European isidiate species Porina hibernica and P. pseudohibernica, which appeared as sister to each other in the analysis. While a particular type of isidiose structure may be reliably characteristic of specific taxa, similarities or differences in these structures do not seem to be useful indicators of phylogenetic proximity or distances among taxa. The morphological trends evident in Porina suggest that multiple transitions from crustose to isidioid or microfruticose growth have arisen repeatedly and in quite different ways within this single genus. At least some of the diverse structures treated within the broad concept of isidia may be representative of the developmental pathways by which fruticose growth forms may arise.

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.

Five species of Schaereria Körb. are known to occur in Australia (including Tasmania). The new species S. australis Kantvilas is described from alpine Tasmania and New South Wales; it is characterized by a thallus lacking lichen substances, apothecia with only brown pigments, and ellipsoid, uniseriate ascospores, 10−17 × 6−9 μm. Also treated are: S. bullata Kantvilas, endemic to Tasmania; S. dolodes (Nyl. ex Hasse) Schmull & T. Sprib., first described from North America and recorded here for the first time from the Southern Hemisphere (Tasmania); the bipolar S. fuscocinerea (Nyl.) Clauzade & Cl. Roux and the Australian endemic S. xerophila Rambold & H. Mayrhofer, both recorded for the first time from Tasmania. The species are illustrated and an identification key is provided.

A novel lichen species occurring on rocks was collected from three different localities within Deosai National Park, Gilgit-Baltistan, Pakistan. Phylogenetic analyses of the nrDNA ITS and nuLSU regions revealed that it clustered within the genus Anamylopsora. Further chemical and morpho-anatomical analyses confirmed its uniqueness, and it is described here as a new species under the name A. pakistanica. The distinguishing characters are: an irregularly squamulose appressed thallus on rocks without rhizines; an epinecral layer up to 25 μm thick; ascospores that are hyaline, simple, thick-walled with a smooth surface; septate paraphyses with a pigmented apical cell in a gel-like matrix; globose to subglobose pycnidia with hyaline and bacilliform pycnidiospores. In particular, the species is distinguished from other members of the genus by morpho-anatomical features including the coloration of the thalli, the presence of a thick lower cortex (up to 100 μm), and the presence of simple, thick-walled ascospores. Specimens were found at altitudes up to 4587 m, the highest elevation yet reported for Anamylopsora. A key and comparison to all existing species of the genus Anamylopsora is also given.

Four species of Porpidia are newly reported from China, including one species new to science (Porpidia crystallina) and three records (Porpidia umbonifera, P. seakensis and P. cf. contraponenda) new to China. Porpidia crystallina is characterized by a macrocarpa-type exciple containing crystals, a Cinereorufa-green epihymenium, large ascospores and a lack of secondary metabolites. Morpho-anatomical, chemical and phylogenetic analyses were carried out to elucidate the placement of the species and to support the delimitation of the new taxon. Detailed taxonomic descriptions, ecological and chemical characters, and illustrations are provided for each species. A key to all known Chinese Porpidia species is also provided.

A new lichen species, Lecanora zeorina Li J. Li & Printzen is described here from the south-west of China. Lecanora zeorina is characterized by its somewhat areolate-squamulose thallus, zeorine to lecanorine apothecia, an epihymenium without crystals around expanded paraphyses tips, an amphithecium with large calcium oxalate crystals and the production of atranorin. A new combination, Lecanora crystalliniformis (B.G. Lee & Hur) Li J. Li & Printzen, is based on Protoparmeliopsis crystalliniformis B.G. Lee & Hur, which was described as a new species from South Korea. Collections from China are almost identical in morphology and chemistry, and are phylogenetically closely related. Phylogenetic reconstructions based on ITS and mtSSU suggest that these two lecanoroid species belong in Lecanora s. str. where they form a sister group to sorediate species such as L. barkmaniana Aptroot & Herk and L. variolascens Nyl. Detailed descriptions, discussions, distributions and phylogenetic trees, based on multiple collections, are presented.

Microsatellite markers can provide valuable information about gene flow and population history. We developed and tested new microsatellites for the nitrophilic lichenized fungus Xanthoria parietina and studied its genetic diversity and structure within the urban area of Munich, Bavaria. We compared its local genetic pattern with that of its photobiont partner Trebouxia decolorans, for which existing microsatellites were applied. For comparison, a reference site with clean air was included in the sampling. We found support for three genetic clusters in the fungus X. parietina, which occurred intermingled in collecting sites. There was a high degree of admixture within fungal populations and individuals, and analysis of molecular variance revealed a lack of population structure in the mycobiont. The Trebouxia photobiont, in contrast, exhibited structured populations which grouped into two to five genetic clusters, and individuals showed less admixture than in the mycobiont. This indicates that the two lichen partners differ in their ability to move around in the landscape. The microsatellite markers we report are polymorphic and are suitable for population genetic studies.

An investigation of the genus Usnea, in the biodiversity hotspot of the Republic of São Tomé and Príncipe in tropical West Africa, is presented here. Fifteen species, or species aggregates, were recorded for the islands: Usnea articulata aggr., Usnea baileyi (Stirt.) Zahlbr., Usnea beckeri P. Clerc & Nadel, Usnea bicolorata Motyka, Usnea erinacea aggr., Usnea exasperata (Müll. Arg.) Motyka, Usnea firmula (Stirt.) Motyka, Usnea krogiana P. Clerc, Usnea longiciliata P. Clerc & Nadel, Usnea nodulosa Swinscow & Krog, Usnea pectinata aggr., Usnea sorediosula Motyka, Usnea submollis J. Steiner, and two undetermined species. Two species of lichen are described as new to science: U. beckeri and U. longiciliata. Both species are characterized by a dense and brittle, dark green thallus, the presence of apothecia surrounded by long cilia-like fibrils, a lack of soredia, and the presence of two unknown substances; however, whereas U. beckeri has a pendant growth form and can reach 25 cm in length, U. longiciliata is differentiated by a shrubby growth form of less than 6 cm. These two species also have different ascospore dimensions. A molecular phylogenetic analysis is presented that lends support to their description as new species. Additionally, Usnea krogiana is noted as new to continental Africa and nine Usnea species or aggregates are noted as new to the Islands of São Tomé and Príncipe in the Gulf of Guinea.

As part of a project aiming to determine the lichenised fungal biodiversity of James Ross Island (Eastern coast of Antarctic Peninsula), we identified three infrageneric taxa which were previously not reported from Antarctica: Farnoldia micropsis (A. Massal.) Hertel, Gyalolechia epiphyta (Lynge) Vondrák and Placidium squamulosum var. argentinum (Räsänen) Breuss. Detailed morphological and anatomical properties of these species along with photographs based on the Antarctic specimens are provided here. In addition, the nrITS, mtSSU and/or RPB1 gene regions of the selected specimens are studied and the phylogenetic positions of the species are discussed. The DNA sequence data for Farnoldia micropsis are provided for the first time. Farnoldia micropsis and Gyalolechia epiphyta are also new to the Southern Hemisphere.

Twenty-eight species of Verrucariaceae are reported from Nepal. One genus and nine species are described as new: Nesothele gen. nov., sister to Staurothele s. lat., with a crustose to squamulose thallus, hymenial algae and 4–8 colourless muriform ascospores per ascus; Nesothele glebulosa sp. nov., resembling N. rugulosa but with smaller perithecia; Thelidium uvidulum sp. nov., producing a thin thallus with soralia, prominent perithecia, and 1-septate ascospores; Verrucaria antepotens sp. nov., having a well-developed thallus with dark-sided areoles, immersed perithecia, and small ascospores 12.5–16.5 μm long; V. lactea sp. nov., resembling V. praetermissa but with larger ascospores and a strongly deviating ITS sequence; V. parvipeltata sp. nov., with brown, basally constricted areoles on an extensive dark prothallus; V. senta sp. nov., with a brown cracked thallus and prominent naked perithecia; Willeya eminens sp. nov., with prominent perithecia, and differing from W. protrudens in its ITS sequence; W. irrigata sp. nov. with a thallus cracked into dark-sided areoles, and relatively large ascospores 28.5–40 μm long; W. nepalensis sp. nov. with a cracked thallus, immersed perithecia and a distinctive ITS sequence. Three species complexes might contain new taxa, but wider geographical sampling is necessary before delimiting species: Thelidium minutulum, Verrucaria elaeomelaena and V. hydrophila. Five new combinations are made: Willeya honghensis comb. nov. (for Staurothele honghensis), Nesothele globosa comb. nov. (for Endocarpon globosum), N. hymenogonia comb. nov. (for Staurothele hymenogonia), N. rugulosa comb. nov. (for Staurothele rugulosa) and N. succedens comb. nov. (for Staurothele succedens). Four species are unidentified.