After a brief historical survey, some current trends in the delimitation of lichen genera are discussed. A widespread tendency is that of elevating any supposedly monophyletic group of species to genus rank. As the term ‘ monophyletic ’ has no lower limit, this is likely to result in an explosive inflation of new genera, in a severe loss of the information carried by generic names and in a high degree of nomenclatural disorder. Five criteria are proposed for the acceptance or rejection of new generic segregates: (1) DNA testing for monophyly, (2) phylogenetic analysis, (3) number of characters used, (4) number of species considered, (5) information content of the new splittings. Upon a critical analysis of several recent generic segregations, a more flexible approach to taxonomic ranks is recommended, and particularly, when most of the suggested criteria are not fulfilled, a more frequent use of the subgeneric rank, which does not imply name changes.

The ability of the internal transcribed spacers (ITS regions) of ribosomal DNA to resolve phylogenetic relationships within the euascomycetous order Arthoniales, focusing on the family Roccellaceae was investigated. The effect of alignment on phylogenetic hypotheses was evaluated. A data matrix from the ITS regions was constructed from 33 specimens representing 14 genera, including the outgroup Arthothelium spectabile. Six different alignments were analysed cladistically using parsimony jackknifing. Most groups in the six trees were congruent and well supported under the different alignment settings. In a conservative analysis, where only unambiguously alignable regions were included, the resolution was low. These results indicate that the ITS regions contain phylogenetic structure, and all information, including the variable regions, should be utilised. A data matrix from the SSU rDNA sequences was constructed for the same taxa. The SSU rDNA tree was less resolved than the ITS trees. There were only minor conflicts between the two sources of data and an incongruence test confirmed that the ITS and SSU rDNA data matrices were not significantly incongruent. The six differently aligned data matrices generated from the ITS regions were each combined with the SSUrDNA data. Simultaneous analysis of the combined data sets is the best approach as it uses all available evidence. As with the ITS trees, most groups in the combined trees were congruent and well supported. The SSU rDNA provided resolution within one clade, otherwise the ITS sequences provided most of the signal in the combined analysis, both at the basal nodes and at the tips of the tree. Molecular data clearly indicates that the fruticose/crustose habits have evolved multiple times even in comparatively small groups as in the family Roccellaceae and that the characters such as fruticose-crustose may be overemphasized in morphological analyses.

Lepraria atlantica is described as new from acidic rocks in the British Isles; it contains porphyrilic acid, cf. rangiformic acid or rarely cf. roccellic acid, and atranorin. It differs from L. cacumimim in the diffuse, powdery thallus. It is morphologically similar to L. jackii, but differs in the possession of porphyrilic acid.

Phoma evemiae sp.nov. on Evemia prunastri and Polycoccum slaptoniense sp.nov. (on Xanthoria parietind) are described as new to science. Three further species are reported from the British Isles for the first time: Dactylospora microspore Etayo,Monodictys anaptychiae (Lindau) D. Hawksw., and Sphaerellothecium araneosum (Arnold) Zopf. Notes are also presented on Bispora lichenumDiederich, Opegrapha physciaria (Nyl.) D. Hawksw. & Coppins, Polycoccum kerneri Steiner, Pronectria xanthoriae Lowen & Diederich, Stigmidium degelii R. Sant., and S. hagenii(Rehm) Hafellner.

Two species of Halecania from Asia, H. lobulata van den Boom & Elix and H. pakistanica van den Boom & Elix are described as new to science. In addition, the new combination Halecania pepegospora (H. Magn.) van den Boom is made. The ecology, distribution and chemistry of some selected species are discussed and a key to the fifteen species known worldwide is given.

Sulzbacheromyces is a recently erected genus in Lepidostromatales, differing from Lepidostroma in the crustose thallus. After the initial discovery of S. caatingae, the only species to be found in Brazil so far, a large quantity of additional data and ITS barcoding sequences for this taxon from a much broader geographical range and different habitats was collected. Phylogenetic analysis under a maximum likelihood framework demonstrated that all specimens are genetically uniform, showing no variation in their ITS, suggesting that S. caatingae has a wide ecological amplitude beyond the Brazilian Caatinga and Atlantic Forest biomes. Detailed descriptions and illustrations of the species are presented, including a map showing the distribution of S. caatingae in the Brazilian semi-arid region and the north-eastern Atlantic rainforest.

Bactrospora perspiralis, B. subdryina, Enterographa mesomela, Graphidastra laii and Lecanographa atropunctata (Roccellaceae) are described as new to science based on specimens collected in the wet subtropical lowlands of northern Thailand and Vietnam. The new Graphidastra is the third species in the genus and was also found in Taiwan.

A taxonomic study of the genus Porpidia in western China revealed two species hitherto unknown to science, Porpidia squamosa and P. shangrila, along with three new records for the country: P. flavicunda, P. soredizodes and P. thomsonii. Detailed taxonomic descriptions, ecological and chemical characters, and illustrations are provided for the new taxa, and brief taxonomic descriptions provided for the newly reported taxa. A key to all known Chinese Porpidia species is also provided.

The criteria set out by the International Union for Conservation of Nature to identify threatened species requires information on population trends which, for priority lichen species within Scotland, is lacking. Collecting such data is problematic as there is a lack of empirical information on the performance of different sampling designs and survey methodologies. Using Pseudocyphellaria norvegica as an example species, we tested differences in the efficiency of 3 transect patterns and a 20 minute search for surveying 100×100 m cells of potentially suitable habitat. The methods were not intended to census the total population of the cells but, rather, to provide a standardized, repeatable estimate of the population density to allow detection of trends through time. We also tested the repeatability of the methods between surveyors. The results provided no evidence to suggest that controlled survey methodologies using fixed transect patterns were any better in terms of consistency between surveyors or numbers of occupied trees found than 20 minute searches of the areas within each 100×100 m cell deemed suitable for the target species by an experienced surveyor. Given that following the fixed transect patterns took approximately twice as long as a 20 minute search, the search method would clearly be more cost-effective when there are large numbers of cells to survey. For all survey methods variability between surveyors was high, meaning that it would be extremely difficult to detect temporal changes in populations, and hence identify population trends. We also examined the extent to which recording presence/absence at the 1 ha scale might improve consistency between surveyors and found that it reduced, but did not eliminate, the surveyor variability. Recording only presence/absence would allow greater numbers of cells to be surveyed using the same level of resources, but would reduce the amount of information available per cell for use in analysis of population trends. We conclude that controlling inter-surveyor variability while collecting adequate data for population trend analysis is a major issue when planning and implementing any large-scale survey of lichen species.

Fifty-six known lichenicolous, non-lichenized Opegrapha (Roccellaceae, Arthoniales) species (containing some undescribed taxa) are listed here, five of which are known from Caloplaca (Teloschistaceae, Teloschistales). Opegrapha vulpina, a new lichenicolous fungus on endolithic Caloplaca subg. Pyrenodesmia (Caloplaca erodens and rarely C. albopruinosa), is described from Europe. A second new species, Opegrapha hellespontica, lichenicolous on Caloplaca aurantia, is described from the European part of Turkey. Two possible sibling species of Opegrapha rupestris s. l. lichenicolous on Caloplaca cirrochroa and C. variabilis s. l., respectively, are discussed in the paper, but have not been described.

Temperature preferences and small-scale distribution patterns of four Dermatocarpon taxa in the catchment areas of two Bulgarian rivers were analyzed. Taxa with an overall alpine or arctic-alpine distribution were restricted to microhabitats with the lowest water and rock surface temperatures. A trend for increasing Dermatocarpon rivulorum thallus diameter and colony size (aggregates of thalli) with decreasing temperature was identified. Data on pH and conductivity of the water for the study sites are provided for all taxa. Dermatocarpon arnoldianum is reported for the first time from Bulgaria, confirmed by ITS sequence data, and its known range extends to South-East Europe. All previous records of D. rivulorum from Bulgaria were based on misidentified specimens of D. arnoldianum. Freshwater taxa of Dermatocarpon are proposed as a tool for monitoring the biological effects of temperature changes due to global climate change. Thallus and colony size are recommended as additional features for monitoring populations of threatened Dermatocarpon species.

The subantarctic genus Orceolina is revised and two species are accepted, i.e. Orceolina antarctica Mull. Arg. R. S. Poulsen Søchting comb. nov. and Orceolina kerguelensis (Tuck.) Hertel. Descriptions of the species are provided. In addition the phylogeny of the genus Orceolina and allied taxa was investigated using nucleotide sequences of the LSU rRNA gene. Sequences from these regions of nine agyrialean fungi were aligned to those of four representatives of Pertusariales used as outgroup. The alignment was analysed cladistically using maximum parsimony. The two Orceolina clustered together within the Agyriaceae. The placement in the family is supported by high bootstrap values and the Kishino-Hasegawa test.

Two hundred and three specimens belonging to the genus Cetrelia from the Soviet Union and also 41 samples from other countries have been analysed by TLC. Eight species were determined in the Soviet Union. In addition two new species, C. orientalis and C. pseudocollata sp. nov. are described. Five morphotypes and six chemotypes have been recognized in the genus: their main characteristics are tabulated in a form that can be used for identification and a key is also included. Evolutionary relationships between the ‘primary’ and ‘secondary’ species related to ‘species-pairs’ are discussed.

The monotypic genus Botryolepraria Canals et al. is described. The type species, B. lesdainii (Hue) Canals et al. is a sterile, cottony, pale green lichen, made of hyphae supporting subterminal bunches of chlorophycean algae.

The new species Micarea corallothallina is described from Serra da Jibóia, Bahia, NE Brazil. It has a gnarled, coralloid, isidiose thallus and pale botryose apothecia. It was found in the Serra da Jibóia, a mountainous range with a maximum elevation of 800 m on smooth bark of trees. This Mata Atlantica fragment is located in the Santa Terezinha municipality, Bahia, NE Brazil, near the Castro Alves municipality boundary. This area can be considered as a rainforest enclave surrounded by Caatinga, and belongs to a disjunct set of mountains that extend from the southern coast of the state to the North-west and North.