The taxonomy of species related to Verrucaria praetermissa is investigated using morphological and molecular data. Verrucaria devensis is closely related to V. praetermissa but distinguished by the darker colour, the thinner and more uneven thallus, and the ITS sequence. This species is based on Leucocarpopsis devensis G. Salisb., which was originally described as the type species of a monotypic genus differing from Verrucaria by the absence of dark pigment. Verrucaria lapidicola is a new species from stones in non-aquatic situations; it is related to V. praetermissa and V. elaeina but differs in the very thin thallus and ITS sequence.

The epiphytic lichen Porina pseudohibernica is described as new. It is characterized by a richly isidiate thallus, 7–8(–9)-septate ascospores and the presence of periphyses. It resembles P. hibernica s. str., differing in the size and septation of ascospores, and in the dimensions of the terete, branched isidia. The new species was found fertile at a single site in the Carnic Alps (SE Alps, Italy), but it is also known in a sterile condition from scattered localities in the humid (sub-)montane belt of Slovenia, the Czech Republic and Ukraine, occurring on smooth bark of Fagus and Carpinus. Porina hibernica is restricted to the coastal lowlands of Atlantic Europe, and it prefers rather dry, base-rich bark of Quercus and Ulmus. The characters previously used to segregate the isidiate European Porina into the genus Zamenhofia are also discussed.

We estimated phylogeny in the lichen-forming ascomycete family Pannariaceae. We specifically modelled spatial (across-site) heterogeneity in nucleotide frequencies, as models not incorporating this heterogeneity were found to be inadequate for our data. Model adequacy was measured here as the ability of the model to reconstruct nucleotide diversity per site in the original sequence data. A potential non-orthologue in the internal transcribed spacer region (ITS) of Degelia plumbea was observed. We propose a revised generic classification for the Pannariaceae, accepting 30 genera, based on our phylogeny, previously published phylogenies, as well as available morphological and chemical data. Four genera are established as new: Austroparmeliella (for the ‘Parmeliella’ lacerata group), Nebularia (for the ‘Parmeliella’ incrassata group), Nevesia (for ‘Fuscopannaria’ sampaiana), and Pectenia (for the ‘Degelia’ plumbea group). Two genera are reduced to synonymy, Moelleropsis (included in Fuscopannaria) and Santessoniella (non-monophyletic; type included in Psoroma). Lepidocollema, described as monotypic, is expanded to include 23 species, most of which have been treated in the ‘Parmeliella’ mariana group. Homothecium and Leightoniella, previously treated in the Collemataceae, are here referred to the Pannariaceae. We propose 41 new species-level combinations in the newly described and re-circumscribed genera mentioned above, as well as in Leciophysma and Psoroma.

The new obligately lichenicolous fungus, Melaspilea tucumana Flakus, Etayo & Kukwa, inhabiting thalli of saxicolous Pertusaria s. lat. is described from Tucumano-Boliviano vegetation in Bolivia. The species is characterized by the gall formation and superficial, lirelliform to branched, aggregated apothecioid ascomata with widely exposed discs. The ascomata of M. tucumana are initially perithecioid and immersed in the host thallus, but become superficial and apothecioid when mature, and thus resemble the genus Buelliella. This may suggest the placement of the new species in Dothideomycetes.

Three new corticolous Arthoniaceae are described from the Chapada do Araripe, an isolated table mountain in the state of Ceará, in NE Brazil. Arthonia stipitata, lichenicolous on unidentified sorediate crusts, with red, tiny, stipitate apothecia, 3-septate ascospores, 10–12×3·0–3·5 µm. Stirtonia lucida with rather small ascigerous areas, lichexanthone and zeorin in the thallus, globose asci, ascospores 8 per ascus, ellipsoid, 17–19×8–10 µm, with occasionally some longitudinal septa. Stirtonia ochracea with rather small ochraceous ascigerous areas, thallus without secondary metabolites, ascospores 8 per ascus, (7–)9(–11)-septate, 47–55×14–20 µm. These species were found during a study aiming at an inventory of the lichen biodiversity of the Cerrado forests in the area, and were not found during earlier ecological studies in the Caatinga forests in the same area. Stirtonia lucida is the first species assigned to this genus which occasionally has some longitudinal septa in the ascospores. Such specimens might be confused with Cryptothecia species.

A world key is given to the species of Pyxine with lichexanthone in the upper cortex. Pyxine pustulata Aptroot & Jungbluth is described as a new corticolous species of Pyxine from São Paulo State in Brazil, with lichexanthone in the cortex, upper surface K−, a yellow to ochraceous medulla and clusters of laminal polysidiangia. Brazil is clearly the centre of Pyxine diversity, with 34 out of c. 70 species known worldwide.

A world key to the 21 species of Stirtonia is presented. Three new Stirtonia species are described from the Neotropics: Stirtonia ibirapuitensis Aptroot, Käffer & S. M. Martins, with whitish to cream amoeboid ascigerous areas with lichexanthone on a greenish thallus without lichexanthone and ascospores of 27–32×9·5–12·5 µm; Stirtonia punctiformis Aptroot & Sipman, with ascigerous structures of thallus colour, consisting of one or more brown asci with brown walls with surrounding tissue, in groups or irregular lines and brown ascospores 61–73×27–35 µm; and Stirtonia viridis Aptroot, L. I. Ferraro, Sipman & M. Cáceres, with ascigerous structures mostly linear, branched and anastomosing, whitish, and contrasting with the often greenish thallus and with ascospores 50–58×15–22 µm. In addition, a specimen of S. neotropica is reported that contains some patches of lichexanthone, S. curvata is reported new to the Neotropics from Brazil and the Netherlands Antilles, and S. nivea is reported new to the Northern Hemisphere from Puerto Rico. Also, Crypthonia divaricatica Aptroot & Sipman, with an irregular, thick thallus with divaricatic and usnic acids and flat white ascigerous areas and macrocephalic 5–9-septate ascospores 20–27×9·5–12·5 µm is described from Mexico. While only one Stirtonia species was known from the Neotropics as recently as 2009, the total number of Stirtonia species known from the Neotropics is now 12, an equal number to the 12 species that are known from the Palaeotropics.

In this study we examined photobiont identity, diversity and selectivity in the genus Bryoria. We focused on B. fremontii and section Implexae in order to determine whether secondary chemistry is correlated with photobiont identity. DNA from two loci for photobionts and three loci for mycobionts was sequenced for both parsimony and Bayesian phylogenetic analyses. A comparison of photobiont and mycobiont phylogenies reveals that most Bryoria species associate exclusively with lineages of the Trebouxia simplex group; only B. smithii was associated with a different photobiont. We conclude that most Bryoria species included in our study are highly selective in their choice of algal partners and that the presence/concentration of different secondary compounds does not correlate with photobiont identity either in section Implexae or in B. fremontii.

Many lichen species have specific environmental requirements for colonization. Old-growth forests contain microhabitats required by a particular suite of lichens. In Ontario, Canada, old-growth forests are increasingly uncommon and the lichen communities within some of these forests are not well known. To better understand the lichen communities that inhabit old-growth forests in the province, we examined the lichen biota on coarse woody debris (CWD) and trees in a red pine (Pinus resinosa) and a white pine (Pinus strobus) dominated stand in northern Ontario. Lichen diversity was assessed on different forms of CWD and trees in each forest. Lichen diversity did not differ significantly between CWD types in the red pine forest, but was significantly different in the white pine forest. There was no significant difference in lichen diversity amongst different decay stages of CWD in either forest. In both forests, lichen communities on stumps, logs, and snags differed from lichen communities present on trees. A variety of CWD types is important for overall lichen species richness in the red pine forest. Our results demonstrate to land managers that different types of old-growth forests are ecologically unique, even those dominated by tree species in the same genus. Management of an old-growth forest should suit its individual ecology.

Across much of lowland Britain, lichen diversity has been dramatically affected by the Industrial Revolution, including the lasting legacy of pollution, and changes in land use including the loss, intensification, or abandonment of traditional woodland management. We sampled preserved epiphytes on historical timbers in vernacular buildings to reconstruct pre-industrial lichen species occurrence for a site in Exmoor, south-west England, and used these data to quantify biodiversity loss that appears related to shifts in woodland composition. A total of 33 lichen epiphyte species were collected from pre-industrial structural timbers, and these were compared with modern lichen occurrence. Based on a direct comparison with species presence-absence in the same 10 km target grid-square, c. 31% of species recorded from the pre-industrial landscape had disappeared from the post-1960 landscape. Based on statistical inference comparing historical records with present-day biogeographical distributions, up to 38% of species could be inferred to be lost. This study presents a surprisingly high figure for these losses for a region in Britain usually recognized as having a relatively unpolluted environment and a diverse set of lichens. Of 12 species that were inferred to be lost, nine are predominantly found on nutrient-rich bark, and in our study on Ulmus, the dominant timber in the archaeological samples. We conclude that shifts in phorophyte distribution and abundance may be more important in this region than previously understood.