Petractis nodispora is described as a new species, characterized by an endolithic thallus with Trentepohlia as photobiont, immersed apothecia, 3-septate, halonate ascospores, and very distinctive multicellular conidia. Nuclear ribosomal SSU and LSU sequences show that it is closely related to P. luetkemuelleri, but its relationship to the type species of Petractis, P. clausa, is unclear.

Two new conidial lichenicolous fungi are described from Spain: Lichenodiplis crespoae on Cyphelium notarisii and Minutoexcipula tephromelae on Tephromela atra. Lichenodiplis crespoae differs from all the described species of the genus in the narrower and shorter conidia, and the host Cyphelium notarisii. Minutoexcipula tephromelae is characterized by subglobose, conidiogenous cells occasionally bearing 1–2 long proliferating extensions, short conidia and by the host Tephromela atra.

Bryoria fremontii and B. tortuosa are the only species in the lichenized ascomycete genus Bryoria known to contain the pulvinic acid derivative vulpinic acid. In B. fremontii this yellow pigment is restricted to the soralia and apothecia, while in B. tortuosa it can occur throughout the thallus. The actual amount of vulpinic acid produced by B. tortuosa is rather variable, however, with intermediate specimens bearing both white and yellow pseudocyphellae. We studied the relationship between the two species with parsimony analysis using four DNA regions: 1) the internal transcribed spacers of the nuclear rDNA including the 5.8S region (ITS), 2) partial sequences from the intergenic spacer of the nuclear rDNA (IGS), 3) partial sequences from the small subunit of the mitochondrial rDNA (mtSSU), and 4) partial sequences from the protein-coding glyceraldehyde-3-phosphate dehydrogenase gene (GAPDH). Our phylogenetic analysis revealed that B. fremontii and B. tortuosa must be regarded as conspecific, but allowing for some genetic differentiation between European and North American populations. Bryoria tortuosa is therefore synonymized with B. fremontii.

Melanotopelia africana is described as new to science from Rwanda (continental Africa) and La Réunion (Mascarenes archipelago). Topeliopsis muscigena is here reported for the first time from La Réunion.

Twenty-three species of epiphytic Caloplaca are recognized in India, of which Caloplaca himalayana Joshi, Y. & Upreti, characterized by thin, continuous, yellowish thallus, numerous ferruginous-red to brownish red, flat to subconvex apothecia with a persistent proper margin and lignicolous habitat, is described here as a new species. Because of the ferruginous coloured apothecial disc, the new species is provisionally placed in the ferruginea group until a taxonomic treatment of the whole group has been carried out. The ferruginea group is characterized by a whitish to grey (rarely yellowish) crustose thallus, a ferruginous to rarely blackish apothecial disc, biatorine to lecanorine exciple, thick-walled spore septa and the chemosyndrome C. The taxonomic affinities of the new taxa with several other taxa, including species of ferruginea group, are discussed. Two new records for India are also recorded: Caloplaca alnetorum Giralt, Nimis & Poelt and C. crocea (Kremp.) Hafellner & Poelt. A key to all the corticolous Caloplaca species occurring in the Indian subcontinent is also provided.

Parmeliella zeylanica is described as a new species in the P. mariana group, although it differs from all known species in the group by not having radiating marginal lobes resting on a distinct mat of rhizohyphae. It is as yet known only from the highlands of Sri Lanka. The new combination Parmeliella leiostroma (Nyl.) P. M. Jørg. is made for a closely related species from the same region, and it is shown that Parmeliella endomilta var. achromatica Makhija & Adawara falls within the variation of Parmeliella mariana (Fr.) P. M.Jørg. & D. J. Galloway, and is not closely related to P. endomilta.

Meridianelia maccarthyana Kantvilas & Lumbsch, gen. et sp. nov., is described, based on collections from Tasmania. This taxon represents only the second member of the family Elixiaceae. It is compared to Elixia flexella (Ach.) Lumbsch and to the superficially similar genus Trapelia. The family Elixiaceae is redefined briefly to account for the inclusion of a second genus.

A corticolous Graphis discovered in the southern part of Venezuela is described as new to science. The new species, Graphis breussii sp. nov., is characterized by rather large, prominent lirellae with striate labia and apically thin complete thalline cover, a completely carbonized exciple, four submuriform ascospores per ascus, and norstictic acid; it belongs in the Graphis acharii group.

Phylogenetic relationships among the hypothetical species pairs Lobaria kurokawae / L. retigera and L. pseudopulmonaria / L. isidiosa were investigated based on TLC techniques and the phylogenetic analysis of the internal transcribed spacers (ITS) nrDNA. Results of TLC demonstrate that L. retigera and L. kurokawae can be chemically distinguished from L. isidiosa and L. pseudopulmonaria by the absence of retigeranic acid. Parsimony analysis of 18 specimens shows two monophyletic clades – a L.retigera lineage and a L. isidiosa lineage—both including their apotheciate counterparts. Unlike the original hypothesis of species pairs, our study reveals transitions from isidiate morphs that have the potential to rarely form apothecia, towards apotheciate morphs that produce no vegetative propagules.

The relationship between thallus size and apothecium density was studied in two umbilicate lichens, Umbilicaria cylindrica and Lasallia pensylvanica, growing in alpine rock surface environments. Samples of the two lichens were collected from the Daisetsuzan National Park, northern Japan. Umbilicaria cylindrica produced many smaller apothecia, whereas L. pensylvanica had larger but fewer apothecia. To explain the differences in reproductive efforts between these two species, we analyzed the lichen data using a hierarchical Bayesian model in which the density of apothecia for each species was predicted by the thallus area and the sky openness index (SOI). The Bayesian model including unobservable effects, i.e. the random effects of individual lichens and rock faces, predicted that the apothecium density for both species increased as the thallus area increased. The estimated coefficient of thallus area to apothecium density for U. cylindrica was larger than that for L. pensylvanica. We also detected a probable positive relationship between SOI and apothecium density for U. cylindrica, whereas none was detected for L. pensylvanica.

The suitability of image analysis by colour-based pixel classification to quantify lichen colonization on the surface of and within marble, travertine and mortar stonework has been investigated. High resolution images of lichenized stonework surfaces were acquired at different field sites using a scanner, thus avoiding invasive surveys, and the percentage cover of lichen species was subsequently measured in the laboratory using dedicated software. Furthermore, microphotographs of polished cross-sections of lichenized marble, travertine and mortar, stained using the periodic acid-Schiff (PAS) method to visualize hyphae, were produced by the same software to quantify hyphal spread within the substratum, a parameter which can be used more successfully than the commonly used depth of hyphal penetration to quantify how much the lichen has affected the conservation of a stone substratum. Significant statistical differences in hue, saturation and intensity (HSI) of the lichen thalli and PAS-stained hyphae, with respect to the lithic substrata, allowed the software to discriminate and quantify the lichen species cover on, and hyphal spread within, the three investigated lithotypes. Since such a quantitative approach highlights the volume of influence of lichens on stonework, where bioweathering processes are likely to develop, it could be used to support decisions on the preservation of our stone cultural heritage.