A thorough chemical, molecular and morphological study has been carried out on a problematic group in the genus Lepraria characterized by lobed, granular thalli with a raised rim and a preference for mosses, rocks and mineral soils in exposed, xeric habitats. The material examined was collected in seven countries of the Mediterranean-Macaronesian region, from chalk, carbonate rocks and derived soils (A-thalli), and from siliceous rocks and derived soils (B-thalli). The results of a phylogenetic analysis based on 93 ITS sequences (29 of which newly obtained) support the identification and the segregation of two taxa at species level, provisionally identified as Lepraria isidiata s. lat., (most of the A-thalli), and L. santosii s. lat. (B-thalli plus the remaining A-thalli), as the observed genetic variability is quite high. Three chemotypes were detected in L. isidiata s. lat., and seven in L. santosii s. lat. The two taxa are morphologically well characterized: in L. isidiata s. lat. the thallus is thicker and the propagules larger than in L. santosii s. lat. The first stages of thallus development from single propagules are described in both species. Some critical remarks are made about the increasing use of the species rank for taxa of Lepraria, which are morphologically and genetically scarcely characterized.

Enterographa fellhaneroides and E. meklitiae are described as new to science from Kakamega Forest in Western Kenya. The latter overgrows the thallus of a foliicolous non-filamentous Coenogonium and the former most probably has the same ecology. Both species appear to be closely related to E. brezhonega and E. epiphyllum.

A comparative review of 57 Lepraria species and 2 varieties is provided together with species descriptions and a key. Lecanora leuckertiana is transferred to Lepraria. In addition some putative taxa by different authors are discussed.

Conservation assessments of lichens have usually been based on scattered and methodologically diverse data. We illustrate the contribution of standardized inventories to conventional data sources by assessing the status of two conspicuous epixylic Cladonia species of conservation concern in Estonia. A time-limited inventory of all lichen species was carried out in 92 stands (2 ha each) in a balanced design of forests and clear-cuts. Cladonia parasitica (previously considered Regionally Extinct) was present in 13 stands with a total of 33 individual records, almost exclusively in dry boreal old-growth forests and clear-cuts. Thirty-six records of C. norvegica (previously six records) were made in 17 stands, most frequently in mature meso-eutrophic forests. On average, 1·5 hours of inventory were needed to discover C. parasitica in a stand, and 2 hours for C. norvegica. The scarcity of old records was probably due to the low local abundance of the species, their habitats being unpopular among lichenologists and expenditure of too short an inventory time in the field. Using habitat and frequency data, we estimate that the national population sizes of the species clearly exceed those set as IUCN criteria for species at risk. The key issue is the expected trend in substratum abundance, which suggests C. parasitica to be Near Threatened. We recommend stratified random sampling as an efficient method to collect quantitative information for lichen flora assessments.

Algal genotypes should freely associate with different lichen fungi that grow in the same confined habitat giving the appearance of low levels of selectivity and specificity. If genetic compatibility between algal and fungal partners limits the combination of partners, then some degree of taxonomic specificity should be evident. This study examined the photobiont composition in a community of epiphytic lichens on Jack Pine to investigate selectivity and specificity. The objectives of the study were to infer algal identity, to infer photobiont dispersal, and to investigate the distribution of algal genotypes relative to the fungal partner. Photobiont variability was determined by Restriction Fragment Length Polymorphism (RFLP) and nucleotide sequences of the Internal Transcribed Spacer (ITS) of ribosomal DNA (rDNA). Seven species of lichen-forming fungi are reported to associate with five divergent algal genotypes, with only one species, Evernia mesomorpha, showing some degree of selectivity and specificity. The algae represent at least two species (Trebouxia jamesii and T. impressa) for the area confined to 200cm2 on the north side of 20 Jack Pine trees. Gene flow was inferred in this tightly defined community of lichenized algae. The algal sharing and inferred gene flow may suggest that soredia provide a means of algal transport and distribution among lichen-forming fungi in the habitat.

The species richness and composition of lichens was quantified for four temperate broad-leaved tree species (Acer platanoides, Fraxinus excelsior, Tilia cordata and Ulmus glabra) in boreo-nemoral forests on the talus slope of the North-Estonian limestone escarpment (North-Estonian Klint). Thirteen study sites were distributed along the klint on a west to east gradient. The effects of tree and stand characteristics and geographical location of a stand on composition and diversity of epiphytic lichens were evaluated by multivariate analyses (DCA, CCA, pCCA) and by general linear mixed models (GLMM). Tree level variables (e.g. bark pH, bryophytes cover and host tree species) explained the largest fraction of the variation in lichen species composition. However, species richness and composition were significantly influenced also by the unique habitat conditions of klint forest (length of the forest fragment, proximity of the stand to the sea and height of the escarpment). A significant correlation between stand locality and lichen diversity on the tree bole was found which is most likely related to local air pollution gradients caused by alkaline cement dust and acid pollutants in the north-eastern part of Estonia.

This study aims to investigate patterns of species richness and abundance in relation to stand age in 71 Picea abies plantations, aged between 9 and 85 years, situated in the oceanic region of Central Norway. The study has shown that plantations within the oceanic spruce forests can support a relatively high number of epiphytic lichen species. Some of the oldest plantations hosted several old-forest associated species, e.g. Hypogymnia vittata, Lobaria pulmonaria, Pseudocyphellaria crocata and Ramalina thrausta. The number of species was influenced significantly by stand age and increased rapidly in stands <20 years old. Stands >30 years old showed no clear increase in species number, except for a high number of species in the two oldest stands. The colonization pattern could be characterized as an additional entrance of species, rather than by a replacement sequence. The probability of occurrence increased steeply at young stand ages (<20 years) for Bryoria spp., Cavernularia hultenii, Platismatia glauca, Parmelia sulcata and Usnea spp. A lower rate of colonization was characteristic for Alectoria sarmentosa, Parmelia saxatilis and Platismatia norvegica. The cover of foliose lichens on the branches showed an almost unimodal response to stand age. The cover of lichens was highest on branches in middle-aged plantations. The reason for the lower lichen cover in late successional stages, compared to middle-aged stands, could be due to reduced light in the lower canopy of mature plantations. Increased rotation cycle, creation of gaps and short distance to sources of propagules are factors suggested to promote species richness and abundance in forest plantations.