Leprocaulon inexpectatum is described here as a new lichen species and the fourth member of the genus known from Europe. It is characterized by the crustose-granulose, blue-grey to bluish green thallus composed of ±discrete, soredia-like granules c. 45–70 μm in diameter, and the production of usnic acid and zeorin. Based on ITS rDNA, the lichen is closely related to the saxicolous American species L. beechingii. The new species is reported here from numerous localities in north-western Italy. It occurs on the bark of oaks, chestnut, and black locust in open deciduous forests, often in floodplain ecosystems. Our investigation of its photobiont identity using ITS, 18S and rbcL demonstrated that its symbiotic partner represents an undescribed species within the genus Symbiochloris (Trebouxiophyceae). We provide an identification key to sterile crustose sorediate lichens containing usnic acid and zeorin found in Europe.

A species new to science, Micarea svetlanae, is described from the southern part of the Russian Far East based on morphological, chemical and molecular data. This species is closely related to M. isidioprasina, which also has the micareic acid, the granular-isidiate thallus with Sedifolia-grey pigment, and crystalline granules in the hymenium and thallus, but differs in the cushion-shaped thallus, the presence of Sedifolia-grey pigment in the hymenium, numerous crystalline granules in the hymenium and hypothecium and 0–2(3)-septate ascospores. The results of the phylogenetic reconstruction place M. svetlanae in the M. prasina group. Morphological features and data on ecology, distribution and secondary metabolites are presented in detail in the paper. This new lichen species is named in honour of the Russian lichenologist Dr Svetlana Tchabanenko, who devoted her life to the study of lichens of the Russian Far East.

Two new species in the genera Diploicia and Physcia are described from the tropical dry forest of Mexico. Both species are supported by morphological, chemical and molecular evidence. Diploicia edulis, a species heavily consumed by invertebrates, is characterized by lecanorine apothecia, a dull brown epihymenium not diffused by a green pigment (K−), a subhymenium conspicuously inspersed with oil droplets, and the diploicin chemosyndrome. We provide the first molecular evidence to support the inclusion of species with lecanorine apothecia in the genus Diploicia. Physcia ornamentalis, previously reported under the name Physcia undulata s. lat. as one of the main construction materials for the bags of a moth caterpillar species (Psychidae), is characterized by a frosted-pruinose thallus, soralia originating in the lobe sinuses, and by lacking soralia in the thalline margin of the apothecia.

A new Philippine foliicolous species, Porina dolichoepiphylla, was discovered from the central part of Mindanao Island, and is described and illustrated here. This new species is characterized by conspicuously longer ascospores, a feature shared only with P. virescens within the Porina epiphylla subgroup but can be distinguished from the latter by its hairless surface, as well as rough thalli with primordia of perithecia. Porina dolichoepiphylla sp. nov. is known only from the type locality on Mt Kitanglad, growing along the frond of Asplenium vittaeforme in a shady lower montane forest. An updated checklist of Porina species in the Philippines with a taxonomic key to the foliicolous species of the Porina epiphylla subgroup is also provided. The discovery of the new lichen species highlights the importance of continued exploration and documentation efforts within the Philippine archipelago.

Rapid advances in species distribution modelling have been facilitated by open availability of ‘big data’ and powerful statistical methods. A key consideration remains the time window over which field recorded occurrence data are sampled to develop a baseline species distribution. Too narrow, and distributions are incomplete and affected by sampling bias, too broad and distributions may fail to meet an assumption of equilibrium, having been affected by dynamic change across a range of different predictors. Lichens are a case in point; being diverse, functionally important and the subject of bioclimatic modelling for conservation assessment, they are nevertheless a specialist taxonomic group that is comparatively less well recorded compared to birds, mammals or vascular plants, for example. In this study, we examined the distribution of the ‘hair-lichen’ Bryoria fuscescens, based on UK record data. We partitioned records into sub-decadal periods (1970s, 1990s, 2010s), and accounting for recording effort, we compared these distributions to three predictors: an historical reconstruction of two different pollutants (sulphur dioxide and nitrogen deposition), and the climate (minimum mean temperature). We asked whether the strength of evidence for the effect of environmental predictors on Bryoria fuscescens distribution varied among the different decades, while also considering a potential for lag-effects. We show that a Bryoria fuscescens distribution that appears static, is dynamic when referenced against patterns of field recording effort. Climate was consistently important in explaining Bryoria fuscescens distribution, which was also affected by the changing pattern of pollution over time. This included a lag-effect of peak sulphur dioxide in the 1970s, and accrued effects of nitrogen deposition that strengthen over time. Overall, we conclude that Bryoria fuscescens has undergone a long-term decline in extent over the last six decades, caused by complex multivariate effects of air pollution, probably combined with climate warming. The ability to resolve these trends for assessment against future conservation targets depends critically on maintaining field identification skills and a sufficiently robust recording effort.