Caloplaca sol is described as a new species from limestone and basic siliceous rocks on the southern and western coasts of Great Britain. It is characterized by a well-developed, crustose, non-placodioid, epilithic, cracked, orange-yellow thallus, almost concolorous apothecia up to 0·66 mm diameter, and ascospores c. 11·0–12·2–13·0 µm long with a septum c. 0·4×the ascospore length. Caloplaca dalmatica is related but differs in the endolithic or only thinly epilithic thallus. Caloplaca marina is darker orange in colour, with more convex areoles, and is mostly confined to the splash zone of the seashore. Caloplaca maritima differs in the typically more convex, sometimes isolated areoles, and often in the presence of a crenulate thalline margin in young apothecia. Caloplaca itiana is newly reported from Great Britain from coastal limestone; it differs from C. sol in the thallus being endolithic or almost so, and from C. dalmatica in the more completely endolithic thallus and the larger ascospores.

The two corticolous species Fuscidea lightfootii (Sm.) Coppins & P. James and F. pusilla Tønsberg are morphologically and chemically similar and it has been suggested that they are conspecific. We investigated the interspecific relationship between F. lightfootii and F. pusilla using ITS, LSU and mtSSU rDNA. The combined multigene phylogeny shows that these species are genetically distinct. They are similar in ascocarp anatomy but in thallus morphology and substratum preferences there may be slight differences between them. Moreover, F. pusilla displays a broader ecological range than F. lightfootii. Even though some morphotypes appeared distinct and may be assigned to one of the two species with some degree of certainty, the use of DNA sequencing is recommended for their identification. Epitypes are designated for both species.

Sporastatia crassulata Yakovchenko & Davydov sp. nov. is described and a phylogenetic analysis (mtSSU) is presented, confirming its distinctness and indicating a sister relationship with S. testudinea. The species is unique among Sporastatia species in having a distinctly squamulose, thick, uneven thallus composed of convex, rounded squamules irregularly ascending in the central part of the thallus. The new combination Sporastatia karakorina (Poelt & Obermayer) Davydov & Yakovchenko is proposed. The type specimen of S. subasiatica was examined. A key to the six species of Sporastatia is given. Mountainous Central Asia appears to be the centre of species diversity and endemism for Sporastatia.

Descriptions, illustrations, discussion and an identification key are presented for six saxicolous and terricolous species of the lichen genus Bacidia De Not. occurring in temperate Australia and Tasmania. Three species are described as new to science: B. lithophila Kantvilas from northern Tasmania, characterized by having only brown apothecial pigments and 3–5-septate, acicular ascospores, 23–35×1·5–2·0 µm; B. littoralis Kantvilas from Tasmania, South Australia (Kangaroo Island) and New South Wales, characterized by green and brown apothecial pigments and acicular, 3–7-septate ascospores, 24–48×2·0–3·5 µm; and B. maccarthyi Kantvilas from New South Wales, with pruinose apothecia and long, filiform, 17–25-septate ascospores, 65–115×2·5–4·0 µm. Three further species are reported for the region for the first time: B. bagliettoana (A. Massal. & de Not.) Jatta (Tasmania), B. curvispora Coppins & Fryday (Tasmania) and B. scopulicola (Nyl.) A. L. Sm. (Tasmania, Victoria).

With more than 180 known species, Leptogium has its greatest richness in tropical regions. Only three species have so far been reported from Antarctica but extensive surveys in the Antarctic Maritime Islands have shown that this is an underestimate. Leptogium antarcticum (non-isidiate, with medulla composed of columnar hyphae), L. marcellii (non-isidiate, with medulla composed of a sponge-like arrangement of hyphae) and L. tectum (isidiate, with medulla composed of columnar hyphae) are described here as new to science. The new species are compared with those already reported for the genus in Antarctica, namely L. crispatellum, L. menziesii and L. puberulum, and an identification key is provided. Sequences of ITS and mrSSU regions were obtained from recently collected L. antarcticum, L. marcellii, L. puberulum and L. tectum specimens. Morphological and anatomical data were compared along with available genetic data in order to delimit these species more accurately, using an integrative approach.

Fuscopannaria leucosticta is a rare and understudied cyanolichen with an interesting and unusual distribution in tertiary relict hotspots worldwide. There is a relatively large population in eastern North America, where it occurs mostly throughout the Appalachian Mountains and reaches its northernmost extent in New Brunswick and Nova Scotia, Canada. The ability to detect this species, and thus determine its habitat requirements, is critical for understanding how it might be affected by human-induced environmental degradation. Maximum entropy modelling with MaxEnt was used to predict the distribution of suitable habitat for this species in Nova Scotia using 62 presence locations, 1405 pseudo-absence locations and four environmental covariates: depth to water table (a proxy for relative soil moisture), distance to the coast and mean annual temperature and precipitation. Our predictive maps identify important habitat features and areas of high suitability in Nova Scotia with an area under the curve value of 0·85. The predicted distribution of this lichen was most affected by temperature. This study elucidates locations as well as species-habitat relationships for F. leucosticta, providing land managers with baseline data that can aid in the discovery of additional populations and provide a better understanding of its ecological requirements which will support the development of sound conservation strategies for this rare lichen.

Atranorin is a secondary metabolite found in many lichens. This compound can act as a photo-buffer, supporting its use as a marker of metabolic response to changes in light. In preliminary trials, atranorin was found to be unstable over time when in solution, potentially precluding its usefulness in this capacity. The present study tests the stability of atranorin in different extraction solvents and at different pH values over time using HPLC analysis. We found that atranorin is most stable in acetonitrile, among six tested solvents, and that the presence of strong acid or a strong base destabilizes the compound. We propose that atranorin breaks down through transesterification in methanol and ethanol until an equilibrium is reached, while a strong base breaks down atranorin through saponification and under acidic conditions, atranorin concentration significantly increases with time. Although atranorin levels were found to be stable in whole thallus extracts from fresh lichens using a leaching method, chemicals isolated using chromatographic separation showed similar breakdown to an atranorin standard. In future work on lichens atranorin should be extracted in acetonitrile or acetone without an added base or acid to yield the greatest stability and thus provide more accurate concentration values of atranorin with time using HPLC. The interactions of atranorin with acid and with chloroform need further study.