Lobaria pulmonaria and other members of the Lobarion were found to inhabit drainage channels below old and large wounds on the trunks of various deciduous trees in stands of long ecological continuity in a forest reserve dominated by Picea abies in southeastern Norway. Such channels were richer in minerals and had a higher pH than normal bark, which was covered with more acidophytic epiphytic communities, mainly the Pseudevernion. Chemical microhabitat differentiation was most clear in edaphically poor sites. The restriction of a previously ubiquitous Lobarion to mineral-rich microsites on stems is probably an effect of acid rain. Since acidification seems to make the Lobarion more dependent upon old and damaged stems, modern forestry probably aggravates the damage caused by acid rain.

The examination of the surface deposit of various lichens with X-ray diffraction methods, correlated with scanning electron microscopical (SEM) studies, have shown that calcium oxalate is present as two different hydrates; weddellite (CaC2O4-(2 + x)H2O), in three slightly different morphologies, and whewellite (CaC2O4H2O). The reason for the formation of calcium oxalate is not known and the presence of the various crystal forms is yet to be explained. However, the various hydrates may have some role in the water balance as they are different in dry and humid sites.

The weathering phenomena resulting from the encrustation of basalt by Pertusaria corallina have been studied by scanning electron microscopy and a variety of other techniques. The rock consists largely of plagioclase felspar (labradorite) and ferromagnesian minerals, the latter often being replaced by hydrothermally formed ferruginous clay minerals. Lichen weathering results in the extensive etching of the primary rock-forming minerals, particularly labradorite, and in the degradation of the clay minerals to yield a thin ochreous crust of poorly-ordered ferruginous (ferrihydrite) and alumino-silicate materials. These changes are brought about principally by the oxalic acid secreted by the mycobiont, a conclusion supported by observations following experimental mineral alteration.

A study of the weathering phenomena brought about by the growth of Lecanora alra on a substrate of magnesium silicate minerals (serpentinite) has been carried out mainly by X-ray diffraction and scanning electron microscopy. The lichen thallus contains appreciable amounts of crystalline magnesium oxalate dihydrate, which occurs as an insoluble extra-cellular precipitate and derives from the decomposition of magnesium silicates (particularly chrysotile) by oxalic acid secreted by the mycobiont. In theory magnesium oxalate dihydrate should be capable of incorporating large amounts of heavy metal ions into its structure, as indeed the electron probe evidence indicates has happened, thus suggesting a mechanism for enabling some lichens to cope with environments that are high in these generally harmful ions. The only weathering product detected in the lichen weathering crust is an X-ray amorphous silica gel which often retains the fibrous morphology of the chrysotile from which it forms.

Changing land use has a major impact on lichen diversity. This study attempts to identify patterns or trends of lichen functional groups along a land use gradient, ranging from natural forests to open agricultural landscape. In eight countries, covering six main European biogeographic regions, lichen vegetation was assessed according to a standardized scheme. Data on reproductive, vegetative and ecological traits was compiled and relative species richness for all classes of all traits calculated. Relationships between the land use gradient and relative species richness of trait classes were analysed. Open and intensively managed landscapes harbour more fertile species while sterile species are relatively more important in forests. This finding is also supported by analyses of different classes of dispersal propagules. The importance of species with the principal photobiont Trebouxia s.l. increases linearly with intensification of land use. A converse pattern is revealed by species with Trentepohlia. Concerning substratum specialization only generalists show an effect along the land use intensity gradient. Their relative species richness decreases from landscapes dominated by forests to open agricultural landscape. A considerable decline in the rare lichen species richness as a result of land intensification is predicted.

The phylogenetic relationships of 16 species of Parmelia s. str. are presented based on sequences of nuITS rDNA from 56 specimens, and β-tubulin gene sequences from 29 collections. Parmelia serrana sp. nov. a Mediterranean species morphologically very close to P. saxatilis is described. Parmelia ernstiae is the sister-group to P. saxatilis s. str., and a further undescribed North American species of the P. saxatilis complex may require recognition. The isidiate P. squarrosa is closely allied to the sorediate P. sulcata, which is paraphyletic. Japanese samples of P. cochleata form a monophyletic group but too few collections of these were studied to reach firm conclusions regarding their relationships. An epitype is selected for the lectotype of Lichen saxatilis to unequivocally fix the application of that epithet.

Two shade-adapted (Lobaria pulmonaria and Cetraria islandica) and two sun-adapted lichen populations (Xanthoria parietina and Cetraria nivalis) were exposed to three irradiance regimes (1: photosynthetic radiation—PAR, 2: PAR+UV-A, 3: PAR+UV-A+UV-B) and two hydration regimes (1: no hydration, 2: daily hydration) in a growth cabinet for three weeks. Shade-adapted thalli had transparent upper cortices without coloured pigments, whereas sun-adapted thalli had coloured UV-B absorbing cortical pigments masking the photobiont. Manipulation of pigment concentration was the third factor used in the factorial design (1: pigments intact, 2: pigments non-destructively extracted from air-dry living thalli by acetone). Inhibition of the photobiont due to PAR alone was severe in the two shade-adapted populations, but no applied UV wavelength bands caused additional aggravation of photoinhibition. Shade-adapted thalli of the ubiquitous C. islandica were more PAR-susceptible than of the rare old forest lichen L. pulmonaria, suggesting that screening by the mycobiont rather than photobiont characteristics, account for their different success in sun-exposed localities. Hydration of shade-adapted species during exposure reduced their photoinhibition substantially, probably because of moisture-activated repair mechanisms. On the contrary, the sun-adapted X. parietina was most phototolerant in the desiccated state, whereas hydration caused increased photoinhibition. When removing the orange cortical pigment parietin, the photoinhibition in moist thalli was aggravated, confirming a PAR-protective function of parietin. No effects of irradiance treatment, pigment extraction (usnic acid), or hydration level were observed in C. nivalis.

In contrast to virtually all other species of ruminants, reindeer (Rangifer arandus) eat substantial amounts of lichens in winter. Several different species of lichens are eaten and most are highly palatable. The chemical composition and the in vitro digestibility of six species of terricolous lichens commonly eaten by reindeer were measured. Ruminal inoculum was obtained in winter from six free-ranging reindeer that had been grazing on natural pastures in northern Norway. Analysis of the plant parts recovered from their rumens confirmed that the animals had been eating a mixed diet that included both lichens and vascular plants. The chemical composition and the in vitro digestibility of the different species of lichens varied considerably between species and genera. Cetraria islandica, C. nivalis and Cladonia arbuscula were highly digestible [69-77% dry matter (DM)], Stereocaulon paschale was poorly digestible (43% DM), whereas Cladonia stellaris and C. gradlis had an intermediate digestibility (56-57% DM). Mixing ladonia stellaris with vascular plants (50:50) had no effect on the in vitro digestibility of the combined substrates. The in vitro digestibility of Cladonia stellaris in inoculum from two captive reindeer which had had no access to lichens was very low (10% DM). This shows that the source of inoculum used for digestibility trials has a major effect on the apparent digestibility of the substrates. Evidently, the extent to which reindeer are able to utilize lichens depends on the species that are selected and on what the animals have been eating recently.

This study of elevation gradients of lichen species richness in Nepal aimed to compare distribution patterns of different life-forms, substratum affinities, photobiont types, and Nepalese endemism. Distribution patterns of lichens were compared with elevational patterns shown by a wide range of taxonomic groups of plants along the Nepalese Himalayan elevational gradient between 200–7400m. We used published data on the elevation records of 525 Nepalese lichen species to interpolate presence between the maximum and minimum recorded elevations, thereby giving estimates of lichen species richness at each 100-m elevational band. The observed patterns were compared with previously published patterns for other taxonomic groups. The total number of lichens as well as the number of endemic species (55 spp.) showed humped relationships with elevation. Their highest richness was observed between 3100–3400 and 4000–4100m, respectively. Almost 33% of the total lichens and 53% of the endemic species occurred above the treeline (>4300m). Non-endemic richness had the same response as the total richness. All growth forms showed a unimodal relationship of richness with elevation, with crustose lichens having a peak at higher elevations (4100–4200m) than fruticose and foliose lichens. Algal and cyanobacterial lichen richness, as well as corticolous lichen richness, all exhibited unimodal patterns, whereas saxicolous and terricolous lichen richness exhibited slightly bimodal relationships with elevation. The highest lichen richness at mid altitudes concurred with the highest diversity of ecological niches in terms of spatial heterogeneity in rainfall, temperature, cloud formation, as well as high phorophyte abundance and diversity implying large variation in bark roughness, moisture retention capacity, and pH. The slightly bimodal distributions of saxicolous and terricolous lichens were depressed at the elevational maximum of corticolous lichens.

A number of physiological processes relevant to the role of lichens in mineral cycling are discussed. Consideration is given to the cellular location of positively-charged cations, showing (a) the benefits of quantifying intracellular elements for the interpretation of toxic metal stress, and (b) how distribution patterns of physiologically essential elements may be altered by desiccation and rehydration under field and laboratory conditions. The quantitative significance of these dynamic processes associated with metal uptake and loss requires verification under field conditions. A modified sequential elution procedure is proposed that enables quantification of insoluble paniculate mineral matter (acquired by wet and dry deposition) in addition to soluble elements in intercellular, extracellular-exchangeable and intracellular sites.

Investigation of two sites in the Caledonian allochthon of the central part of the Scandinavian peninsula has shown that several copper tolerant lichens occur on cupriferous substrates. Analysis of the thalli of two of these species, Acarospora rugulosa and Lecidea theiodes, using atomic absorption spectroscopy, X-ray diffraction, infrared spectroscopy and electron probe microanalysis has revealed that copper occurs at high concentrations (5% Cu dry weight) principally as crystals of copper oxalate (1–5 μm diam) encrusting the fungal hyphae within the medulla.

The genetic diversity of photobionts in the lichen Protoparmeliopsis muralis was examined to determine the identity of the photobiont and the level of selectivity for the photobiont by the mycobiont. Forty ITS rDNA sequences of photobionts from thirty nine specimens of Protoparmeliopsis muralis have been determined. The photobiont species were identified both by direct comparison with the available sequences and by phylogenetic analysis. The sequences obtained from P. muralis specimens belonged to different Trebouxia clades. The most common photobionts were T. incrustata and an unidentified lineage, here named as “muralis I”. Less common photobionts were T. asymmetrica and T. gigantea. Two unidentified Trebouxia spp. and a photobiont that belonged to the clade that includes T. impressa, T. flava and T. potteri were also found to be associated with P. muralis. Such flexibility has not been reported to date. Moreover, two different photobionts were found in a single specimen. They belonged to the T. gigantea clade and “muralis I” lineage. The low level of selectivity with respect to the photobiont may constitute an important aspect in that Protoparmeliopsis muralis is one of the most successful urban lichens in the world.

Although various eukaryotic organisms, such as arthropods, endolichenic/lichenicolous fungi, and nematodes, have been isolated from lichens, the diversity and structure of eukaryotic communities associated with lichen thalli has not been well studied. In addressing this knowledge gap, we used bar-coded pyrosequencing of 18S rRNA genes to survey eukaryotes associated with thalli of three different lichen species. In addition to revealing an expected high abundance of lichen biont-related 18S genes, sequences recovered in our survey showed non-biont fungi from the Ascomycota also have a substantial presence in these thalli. Our samples additionally harboured fungi representing phyla (Blastocladiomycota, Chytridiomycota) that have not been isolated previously from lichens; however, their very low abundance indicates an incidental presence. The recovery of Alveolata, Metazoa, and Rhizaria sequences, along with recent work revealing the considerable bacterial diversity in these same samples, suggests lichens function as minute ecosystems in addition to being symbiotic organisms.

The generic classification of Lobariaceae based on a three-gene phylogeny of mtSSU, nuLSU and ITS data, with special reference to the genus Lobariella, is reassessed. Twelve well-supported clades are recognized within Lobariaceae, which correlate with morpho-chemical and ecological features and are suggested to represent distinct generic lineages within the family. Lobaria s. lat. forms at least six lineages: Lobaria s. str. (type L. pulmonaria), the Pseudocyphellaria anomala group, for which the genus Anomalobaria is introduced (type A. anomala), Lobarina (type L. scrobiculata), Ricasolia (type R. amplissima; syn.: Dendriscocaulon), the Sticta wrightii group, for which the genus Dendriscosticta is introduced (type D. wrightii), the Lobaria peltigera group, for which the genus Yoshimuriella is introduced (type Y. fendleri), and Lobariella (type L. crenulata; syn: Durietzia nom. illeg.). Pseudocyphellaria s. lat. comprises four lineages, each of which having genus-level names available: Crocodia (type C. aurata), Parmostictina (type P. hirsuta), Podostictina (type P. endochrysoides), and Pseudocyphellaria (type P. crocata). The Pseudocyphellaria anomala group (Anomalobaria) comes out sister to Lobaria s. str., whereas Sticta s. lat. forms two unrelated lineages, Sticta s. str. (type S. sylvatica) and the S. wrightii group (Dendriscosticta), which is closely related to Lobariella and the Lobaria peltigera group (Yoshimuriella). Although these twelve clades can be organized into three larger clades that largely correspond to the traditional genera Lobaria, Pseudocyphellaria, and Sticta, the clade support for Pseudocyphellaria s. lat., as well as the distribution of morpho-chemical characters over the topology, does not favour such a conclusion. In particular, the most relevant characters traditionally used to separate these genera, pseudocyphellae and/or cyphellae, are found in at least two of the three larger clades (some species of Sticta having pseudocyphellae rather than cyphellae). The strongly supported Lobaria s. lat. clade includes species with and without cyphellae and pseudocyphellae (both on the lower side), which defies the traditional classification using these characters. Based on an expanded ITS phylogeny, Lobariella itself is emended to include 26 species, and a key is presented to all species. The following three genera and 19 species are described as new: Anomalobaria B. Moncada & Lücking gen. nov., Dendriscosticta B. Moncada & Lücking gen. nov., Yoshimuriella B. Moncada & Lücking gen. nov., Lobariella angustata B. Moncada & Lücking sp. nov., L. auriculata B. Moncada & Lücking sp. nov., L. ecorticata B. Moncada & Lücking sp. nov., L. flavomedullosa B. Moncada, Betancourt-Macuase & Lücking sp. nov., L. isidiata B. Moncada & Lücking sp. nov., L. nashii B. Moncada & Lücking sp. nov., L. olivascens B. Moncada & Lücking sp. nov., L. pallidocrenulata B. Moncada & Lücking sp. nov., L. papillifera B. Moncada & Lücking sp. nov., L. parmelioides B. Moncada & Lücking sp. nov., L. peltata B. Moncada & Lücking sp. nov., L. pseudocrenulata B. Moncada & Lücking sp. nov., L. reticulata B. Moncada & Lücking sp. nov., L. rugulosa B. Moncada & Lücking sp. nov., L. soredians B. Moncada, Betancourt-Macuase & Lücking sp. nov., L. spathulifera B. Moncada & Lücking sp. nov., L. stenroosiae B. Moncada & Lücking sp. nov., L. subcorallophora B. Moncada & Lücking sp. nov., and L. subcrenulata B. Moncada & Lücking sp. nov. Further, the following 15 new combinations are proposed: Anomalobaria anomala (Brodo & Ahti) B. Moncada & Lücking comb. nov. [Pseudocyphellaria anomala Brodo & Ahti], A. anthraspis (Ach.) B. Moncada & Lücking comb. nov. [Sticta anthraspis Ach.; Pseudocyphellaria anthraspis (Ach.) H. Magn.], Dendriscosticta platyphylla (Trevis.) B. Moncada & Lücking comb. nov. [Lobaria platyphylla Trevis.; Sticta nylanderiana Zahlbr.], D. platyphylloides (Nyl.) B. Moncada & Lücking comb. nov. [Sticta platyphylloides Nyl.], D. oroborealis (Goward & Tønsberg) B. Moncada & Lücking comb. nov. [Sticta oroborealis Goward & Tønsberg], D. praetextata (Räsänen) B. Moncada & Lücking comb. nov. [Sticta platyphylla var. praetextata Räsänen; S. praetextata (Räsänen) D. D. Awasthi], D. wrightii (Tuck.) B. Moncada & Lücking comb. nov. [Sticta wrightii Tuck.], Lobariella corallophora (Yoshim.) B. Moncada & Lücking comb. et stat. nov. [Lobaria exornata var. corallophora Yoshim.], Yoshimuriella carassensis (Vain.) B. Moncada & Lücking comb. nov. [Lobaria carassensis Vain.], Y. corrosa (Ach.) B. Moncada & Lücking comb. nov. [Sticta dissecta var. corrosa Ach.; Lobaria corrosa (Ach.) Vain.], Y. deplanata (Nyl.) B. Moncada & Lücking comb. nov. [Ricasolia subdissecta f. deplanata Nyl.; Lobaria deplanata (Nyl.) Yoshim.], Y. dissecta (Sw.) B. Moncada & Lücking comb. nov. [Lichen dissectus Sw.; Lobaria dissecta (Sw.) Raeusch], Y. fendleri (Tuck. & Mont.) B. Moncada & Lücking comb. nov. [Sticta fendleri Tuck. & Mont.; Lobaria fendleri (Tuck. & Mont.) Lindau], Y. subcorrosa (Nyl.) B. Moncada & Lücking comb. nov. [Ricasolia subcorrosa Nyl.; Lobaria subcorrosa (Nyl.) Vain.], and Y. subdissecta (Nyl.) B. Moncada & Lücking comb. nov. [Ricasolia subdissecta Nyl.; Lobaria subdissecta (Nyl.) Vain.].

In the course of an ongoing systematic and taxonomic revision of the lichen family Graphidaceae (including Thelotremataceae), we present world-wide keys to the currently accepted thelotremoid genera and species, excluding the columellate taxa and their relatives of the Ocellularia-Myriotrema-Stegobolus clade (Melanotrema, Myriotrema, Ocellularia, Ocellularia clandestina group, Redingeria, Stegobolus), which will be treated in a forthcoming paper. The keys include all genera and species with chroodiscoid, lepadinoid, and topeliopsidoid apothecia and other taxa featuring periphysoids or fibrils, and their relatives. Taxa keyed out to genus and species level are Acanthotrema, Chapsa, Chroodiscus, Diploschistes, Fibrillithecis, Gyrotrema, Leptotrema, Leucodecton, Melanotopelia, the ‘Ocellularia’ cruentata group, Pseudoramonia, Reimnitzia, Schizotrema, Thelotrema, Topeliopsis and Wirthiotrema. Over 260 species are treated, including a few yet unnamed taxa. The following taxonomic and nomenclatural novelties are introduced: Acanthotrema frischii Lücking sp. nov., Chapsa aggregata (Hale) Sipman & Lücking comb. nov., C. albida (Nyl.) Lücking & Sipman comb. nov.; C. albomaculata (Sipman) Sipman & Lücking comb. nov., C. boninensis (Tat. Matsumoto) Rivas Plata & Mangold comb. nov., C. elabens (Müll. Arg.) Rivas Plata & Mangold comb. nov., C. imperfecta (Hale) Rivas Plata & Lücking comb. nov., C. laceratula (Müll. Arg.) Rivas Plata & Lücking comb. nov., C. magnifica (Berk. & Broome) Rivas Plata & Lücking comb. nov., C. meghalayensis (Patw. & Nagarkar) Lumbsch & Divakar comb. nov., C. meridensis (Kalb & Frisch) Lücking, Lumbsch & Rivas Plata comb. nov., C. mirabilis (Zahlbr.) Lücking comb. nov., C. neei (Hale) Mangold & Lücking comb. nov., C. paralbida (Riddle) Rivas Plata & Lücking comb. nov., C. pseudoexanthismocarpa (Patw. & C. R. Kulk.) Rivas Plata & Lücking comb. nov., C. pulvereodisca (Hale) Rivas Plata & Mangold comb. nov., C. scabiomarginata (Hale) Rivas Plata & Lücking comb. nov., C. waasii (Hale) Sipman & Lücking comb. nov., Fibrillithecis argentea (Müll. Arg.) Rivas Plata & Lücking comb. nov., F. carneodisca (Hale) Rivas Plata & Lücking comb. nov., F. confusa Lücking, Kalb & Rivas Plata spec. nov., F. diminita (Hale) Rivas Plata & Lücking comb. nov., F. eximia (R. C. Harris) Rivas Plata & Lücking comb. nov., F. fissurata (Nagarkar & Hale) Rivas Plata & Lücking comb. nov., F. gibbosa (H. Magn.) Rivas Plata & Lücking comb. nov., Leucodecton desquamescens (Vain.) Lücking comb. nov., L. oxysporum (Redinger) Lücking comb. nov., Schizotrema cryptotrema (Nyl.) Rivas Plata & Mangold comb. nov., Thelotrema patwardhanii (Hale) Rivas Plata & Mangold comb. nov., Topeliopsis guaiquinimae (Sipman) Rivas Plata & Mangold comb. nov., and T. tuberculifera (Vain.) Rivas Plata & Mangold comb. nov. Using the examples of Fibrillithecis halei s. lat., Leucodecton compunctellum s. lat., and Thelotrema monosporum s. lat., we show how difficult species complexes can be flexibly treated in a key, allowing for either a broad concept or the distinction of several individual taxa.

Primers for amplification and sequencing of partial glyceraldehyde-3-phosphate dehydrogenase (gpd) gene were designed for lichenized fungi. The 5’ gpd primer is most probably fungal specific, since a BLAST search in GenBank found identical sequences only from ascomycetous taxa, whereas the 3’ gpd primer was more universal. Utility of the gpd primers and previously designed beta-tubulin primers was tested in nine lichen taxa. Both the gpd and beta-tubulin primer pairs amplified in most of the taxa examined: the gpd primers generated a c. 1100 nucleotide fragment, whereas the PCR product obtained from the beta-tubulin primers was c. 900 nucleotides long. The gpd amplification products of Cladonia arbuscula and C. rangiferina were sequenced and both were found to contain three introns, the length of which varied between 49 to 83 nucleotides. To examine the applicability of gpd sequences in resolving relationships within Ascomycota, trees were calculated from 22 fungal gpd sequences obtained from GenBank together with the two Cladonia sequences using parsimony jackknifing. The gpd tree was compared with the SSU rDNA tree of the respective species (or genera). A similar analysis of the beta-tubulin gene was not performed, because only a few beta-tublin sequences from the same taxa were available in GenBank. The gpd tree was well resolved but in conflict with the SSU rDNA tree. In contrast to the SSU rDNA tree, the gpd tree did not support the monophyly of the Ascomycota. Analysis of the combined data set produced a tree very similar to that of the SSU rDNA data. However, the relationship of Lecanorales to the other orders remained unresolved. Even though gpd and beta-tubulin are highly conserved proteins, the third codon positions and introns are variable and both genes have the potential for inferring phylogenetic relationships at the lower taxonomic levels in the lichenized fungi. The two genes may be useful even below species level, depending on the species investigated.

Lichen mycobionts are typical representatives of their fungal classes but differ from non-lichenized taxa by their manifold adaptations to symbiosis with a population of minute photobiont cells. Most interesting are the morphologically complex macrolichens, the fungal partner of which competes for space above ground and contains photobiont cells optimally positioned for gas exchange and illumination. Such thalli are the product of an amazing hyphal polymorphism, with multiple switches between polar and apolar growth and hydrophilic or hydrophobic cell wall surfaces. Hydrophobic sealing of the apoplastic continuum between the partners by means of mycobiont-derived hydrophobic compounds canalizes the fluxes of solutes during the often quite dramatic de- and rehydration processes and keeps the algal layer gas-filled at any level of hydration. The impressive tolerance of drought, heat and cold stress of most lichen-forming fungi and their photobionts is due to a very interesting combination of protective and repair mechanisms at the cellular level, the molecular bases of which remain to be explored. Contemporary experimental lichenology is analysed and strategies are proposed aimed at better integration into mainstream biology.

In this study, the symbiont cells of several endolithic lichens colonizing granite in continental Antarctica and the relationships they have with the abiotic environment were analyzed in situ, in order to characterize the microecosystems integrating these lichens, from a microecological perspective. Mycobiont and photobiont cells, the majority classified as living by fluorescent vitality testing, were observed distributed through the fissures of the granite. The fact that extracellular polymeric substances were commonly observed close to these cells and the features of these compounds, suggest a certain protective role for these substances against the harsh environmental conditions. Different chemical, physical and biological relationships take place within the endolithic biofilms where the lichens are found, possibly affecting the survival and distribution of these organisms. The alteration of bedrock minerals and synthesis of biominerals in the proximity of these lichens give rise to different chemical microenvironments and suggest their participation in mineral nutrient cycling.

Lichens epiphytic on olive trees were used as biomonitors of sulphur dioxide pollution in La Spezia (Northern Italy). The method adopted was designed to avoid subjectivity at all stages, from the sampling strategy to data analysis. Thus, lichen data are expressed by an index that does not depend on any sensitivity scale; data analysis relies on multivariate methods of classification and ordination, and the pollution maps have been produced by automatic mapping programmes. The index, based on the frequency of species within a sampling grid, showed a very high statistical correlation with pollution data measured by recording gauges. The results of classification and ordination indicate that Parmelia caperata is the species with a distribution best related to the lichen index. The quality of air pollution data obtained from biomonitors is discussed.

An identification key is presented for the accepted species of the lichen genera Anthracothecium (comprising 5 species) and Pyrenula (with 169 species, including 7 still undescribed). The key also contains some similar taxa and is complete for Blastodesmia (1 species), Sulcopyrenula (4 species), and Eopyrenula (6 species), but not for others such as Aptrootia, Architrypethelium, and Lithothelium, of which only the corticolous brown-spored taxa are treated. The following new combinations were found to be necessary: Anthracothecium interlatens (Nyl.) Aptroot, Pyrenula breutelii (Müll. Arg.) Aptroot, Pyrenula ceylonensis (Ajay Singh & Upreti) Aptroot, Pyrenula fusispora (Malme) Aptroot, Pyrenula gibberulosa (Vain.) Aptroot, Pyrenula lyoni (Zahlbr.) Aptroot, Pyrenula papillifera (Nyl.) Aptroot, Pyrenula platystoma (Müll. Arg.) Aptroot, Pyrenula schiffneri (Zahlbr.) Aptroot, Pyrenula welwitschii (Upreti & Ajay Singh) Aptroot, and Sulcopyrenula subglobosa (Riddle) Aptroot. Pyrenula sexluminata Aptroot is a new name for Pyrenula quinqueseptata Aptroot, and Pyrenula neosandwicensis Aptroot is a new name for Anthracothecium sandwicense Zahlbr. In addition, all known and many novel synonyms are cited, and the disposition of all other taxa in the two genera Anthracothecium (with 155 names) and Pyrenula (with 745 names) and their generic synonyms. Bogoriella was found to be an older name for Mycomicrothelia.