The chemical and ultrastructural features of the interface formed by different biotypes of saxicolous lichen species with their rock substrata were investigated in the semiarid habitat of the SE Iberian Peninsula and the relationships between the bioweathering patterns observed and lichen colonization selectivity towards the different rock substrata evaluated. Xanthoria parietina was able to fix to the rock substratum by the adherence of single cell walls from the lower cortex. Neofuscelia pulla used rhizines and loose groups of hyphae for attachment of the thallus to the rock. Colonization by the foliose lichen species was confined to the rock surface, while Diploschistes diacapsis was also able grow below the surface showing two types of hyphal growth. Minerals in close contact with cell walls were biochemically and biophysically weathered, but hyphae showing calcium oxalate crystals did not appear to be directly involved in the patterns observed. The textural characteristics of the substratum seemed to be related to the type of microorganism colonization: sedimentary rocks were more deeply colonized by lichens and other chasmolithic microorganisms than volcanic material. Calcium oxalate crystals were found in the medulla of N. pulla but not at the lichen-substratum interface. Crustose lichens such as D. diacapsis showed calcium oxalate crystals in the upper cortex and over the outside of fungal medullary hyphae but not in direct contact with the rock surface. Calcium oxalate precipitation seems to be related to the different metabolic activities of the mycobiont within the lichen thallus and to different species. D. diacapsis inhibits the growth of other microorganisms in close proximity to the thallus, whereas foliose species were associated with several communities of microorganisms.

Based on morphological, anatomical, chemical, ecological and molecular evidence, Blarneya is synonymized here with Tylophoron. The molecular phylogeny derived from sequences obtained from sporodochia of Blarneya places this genus, described to accommodate an anamorphic lichen with white cushion-shaped sporodochia, within Tylophoron. This conclusion is further supported by the discovery of Tylophoron-type ascomata emerging directly from thalli with Blarneya-type sporodochia and producing identical hyaline conidia. In one specimen pycnidia were also observed. This represents a surprising variety of morphologically different conidiomata. A different anamorphic type was previously reported from Tylophoron, and this is confirmed here by molecular analysis for T. moderatum: besides thalli with ascomata this species has anamorphic thalli with an irregularly delimited brown sporodochial felt and brown conidia. Ascomata are not known from these entirely anamorphic thalli, whereas they do occur infrequently in Tylophoron species with Blarneya-type sporodochia. A key to all currently accepted species of Tylophoron is provided. In addition to the corticolous Tylophoron hibernicum, confined to humid forests, two saxicolous species with Blarneya-type sporodochia are described here as new: T. galapagoense, known only from Galapagos, differs from T. hibernicum by a thicker, more compact, beige rather than white, more strongly C+ red thallus, growing below sheltered rock overhangs in dry forests; T. stalactiticum has a C− thallus with stipitate, white, C+ red sporodochia; the species is known only from a single locality in Tenerife, on a large slope with volcanic boulders.

The genus Inoderma (Ach.) Gray is lectotypified with Inoderma byssaceum and resurrected for a small group of species in Arthoniaceae with elevated, white pruinose pycnidia, immersed to adnate white pruinose apothecia and a weakly gelatinized hymenium. Inoderma nipponicum is described from Japan, I. afromontanum from Uganda and the European Lecanactis subabietina is transferred to the genus. Sporodophoron is described for a small group of species in Arthoniaceae related to Inoderma but with a unique type of sporodochia instead of pycnidia. Sterile specimens of this new genus resemble species of Tylophoron but differ in the rounded angular to elliptical to short cylindrical, 0–2-septate sporodochial conidia with unevenly thickened walls which are formed apically in zigzag-shaped and occasionally branched chains. Sporodophoron further differs in thallus chemistry and is genetically distinct. Tylophoron americanum and Schismatomma cretaceum are transferred to Sporodophoron, and the new species S. gossypinum from Japan and S. primorskiense from eastern Russia are described. The genus Glomerulophoron is described for a single species from Mauritius, G. mauritiae, differing from Sporodophoron in the tightly coiled chains of sporodochial conidia and being genetically distinct. A phylogenetic tree showing the position of Inoderma, Sporodophoron and Glomerulophoron in Arthoniaceae is presented. A key to all species of Arthoniaceae with sporodochia or elevated white pruinose pycnidia is presented. Arthothelium spectabile, the type of the large heterogeneous genus Arthothelium, is confirmed for the cryptothecioid subclade in Arthoniaceae.

The suitability of image analysis by colour-based pixel classification to quantify lichen colonization on the surface of and within marble, travertine and mortar stonework has been investigated. High resolution images of lichenized stonework surfaces were acquired at different field sites using a scanner, thus avoiding invasive surveys, and the percentage cover of lichen species was subsequently measured in the laboratory using dedicated software. Furthermore, microphotographs of polished cross-sections of lichenized marble, travertine and mortar, stained using the periodic acid-Schiff (PAS) method to visualize hyphae, were produced by the same software to quantify hyphal spread within the substratum, a parameter which can be used more successfully than the commonly used depth of hyphal penetration to quantify how much the lichen has affected the conservation of a stone substratum. Significant statistical differences in hue, saturation and intensity (HSI) of the lichen thalli and PAS-stained hyphae, with respect to the lithic substrata, allowed the software to discriminate and quantify the lichen species cover on, and hyphal spread within, the three investigated lithotypes. Since such a quantitative approach highlights the volume of influence of lichens on stonework, where bioweathering processes are likely to develop, it could be used to support decisions on the preservation of our stone cultural heritage.

Non-saxicolous lecideoid lichens form a diverse and polyphyletic group of species with a worldwide distribution. The phylogenetic relationships of the taxa and major clades are still largely unresolved. Here we introduce a new genus Palicella Rodr. Flakus & Printzen for Lecidea glaucopa Hook. f. & Tayl. and two closely related species. Our molecular phylogenetic results, based on maximum likelihood and Bayesian phylogenetic trees, and a combined dataset of five gene loci (ITS, nrLSU, mrSSU, RPB1 and RPB2), indicate that Palicella forms a monophyletic clade sister to Lecanora symmicta and Pyrrhospora quernea. The new genus is characterized by biatorine apothecia, which are often darkened (by the pigment Cinereorufa-green), an exciple of radiating, narrow hyphae with strongly elongate lumina, a hymenium with branched and sparsely anastomosed paraphyses, an ascus with a broad axial body surrounded by a distinct darker staining layer, and narrowly ellipsoid ascospores. Atranorin is present in all, usnic acid in two and pannarin in one species of the genus. Three new combinations are proposed: Palicella filamentosa (Stirt.) Rodr. Flakus & Printzen, P. glaucopa (Hook. f. & Taylor) Rodr. Flakus & Printzen, and P. schizochromatica (Pérez-Ortega, T. Sprib. & Printzen) Rodr. Flakus & Printzen. The molecular phylogenetic analysis confirms that Lecidea hercynica Hauck & Schmull is a synonym of P. filamentosa. An identification key to the species is provided.

Hauck & Huneck (2007) and Hauck et al. (2007) established that lichen secondary chemistry is related to metal absorption in the apoplast of lichens. Depsidones occurring in the medulla of the Mn2+ and Cu2+-sensitive epiphytic lichen Hypogymnia physodes were found to reduce the absorption of Mn2+ and Cu2+ at cation exchange sites (Hauck & Huneck 2007). Several lichen substances, belonging to the depsidones, depsides, anthraquinones, or pulvinic acid derivatives, are known to absorb Fe3+ (Engstrom et al. 1980; Hauck et al. 2007). Occurrence of such lichen substances in lichens of Fe-poor sites, but rarity in lichens from Fe-rich sites suggests that they promote the intracellular uptake of Fe3+ (Hauck et al. 2007). In Acarosporion sinopicae lichens specialized on Fe-rich rock and slag, only two efficient Fe3+ absorbers are known, viz. the depsidone norstictic acid and the pulvinic acid derivative rhizocarpic acid. Their occurrence in Acarosporion sinopicae lichens is attributed to the fact that they reduce the absorption of Fe2+ at cation exchange sites despite their high affinity to Fe3+ (Hauck et al. 2007). The observations by Engstrom et al. (1980), Hauck & Huneck (2007) and Hauck et al. (2007), which were made in experiments with isolated lichen substances, suggest that these secondary metabolites control metal homeostasis in lichens by reducing the absorption of selected metal ions in the apoplast and by promoting the uptake of Fe3+.

Epiphytic lichens were recorded on wayside trees in the Netherlands. Four statistical methods were used to detect the relationship between presence and abundance of lichen species and measured atmospheric concentrations of SO2, NO2 and NH3. The observed relationships were compared to published indicator scales of lichen sensitivity to atmospheric pollution. For SO2, a good agreement was found between all scales and calculated sensitivities based on presence or absence of species. For NO2 and NH3 the correspondence was less obvious. The sensitivity to NH3 was inversely related to Wirth's;s acidity indicator positively to NH3 tend to be sensitive to SO2 and NO2.

Several specimens of a lichen-inhabiting Tremella, inducing the formation of pale yellow, dark brown or black galls on species of Diploschistes, have been collected in three localities in Sweden and in one locality in the USA. Morphological and molecular studies confirm that this material represents a single species, which differs from other described Tremella species in the combination of gall morphology, basidium morphology, basidium and basidiospore sizes, presence of thick-walled hyphidia, and a different host-selection. We consequently describe this fungus as Tremella diploschistina sp. nov., on the basis of morphology and phylogenetic analyses of ITS and nLSU sequences. The phylogenetic analyses reveal that the fungus clearly belongs in Tremella, although the relationships with other species in the genus remain unclear.

In order to examine genetic variation and population structure of the widespread lichen-forming ascomycete Xanthoria parietina from similar habitats, but different sites in Scandinavia, we investigated seven populations in Scania, southernmost Sweden, and compared the results with a corresponding study on Storfosna, central Norway. Sequence variations of the nuclear ribosomal DNA were used as molecular markers, for both a part of the IGS region and the complete ITS1-5.8S-ITS2 region. The amount of genetic variability observed was comparable in the two investigations. Divergence between populations in different habitats found in the previous study was also present in this study. Xanthoria parietina is genetically differentiated between habitats with no evidence of restricted gene flow between populations in the same habitat at the present spatial scale, at least at sites along the coast of Scandinavia. Differentiation between habitats is considerable at both study sites, which we attribute to restricted gene flow between habitats, i.e. habitat isolation.

Descriptions and a key for identification of lichenicolous Arthonia species with red to purple pigments reacting with K are provided. The previously reported species, A. cryptotheciae and A. mazosiicola (as A. mazosiae), are here validly described, and A. haematostigma, A. tavaresii and A. destruens var. nana are new to science. The genus Helicobolomyces is introduced with the type species H. lichenicola, being based on the anamorph of A. cinnabarinula.

Polysaccharides from thalli of Lasallia pustulata were extracted and characterized. The major fractions were characterized as pustulan, a β-glucan-chitin complex and a β-(1→3)-glucan. Other polysaccharides, which are minor components (less than 5%) solubilized with water from the alkali extracts of thalli, were shown to be galactomannans with a backbone of α-(l→6)- mannose partially substituted at positions 2 by galactofuranose and/or mannopyranose side chains of variable length. The relationship between these polysaccharides and those obtained by the same method from free-living fungi is discussed. The proportion or composition of the different polysaccharides studied was not affected by seasonal environmental conditions over a 2-year period.

Central Europe in general is poor in Teloschistaceae lichen crusts (Caloplaca s. lat.). Diversity of these lichens is increased by the occurrence of some Arctic, Mediterranean and continental species, which are here close to the limits of their range. Examples include:

1. 1) Caloplaca interfulgens, previously known from arid territories of northern Africa and western Asia, is recorded, surprisingly, from Austria, Czech Republic, Germany, Slovakia and southern Russia. In Central Europe, it is restricted to scattered xerothermic limestone outcrops.

2. 2) Caloplaca scabrosa, previously known only from Svalbard, is recorded from the Sudetes in the Czech Republic. It is similar to, but not conspecific with, C. furfuracea. Its diagnostic characters include a blastidiate thallus and the presence of atranorin. Our results show that atranorin is absent in the majority of taxa related to C. furfuracea with only two exceptions: the sample from Eastern Carpathians, here called C. aff. scabrosa, and in one Sudetan sample identified as C. crenularia.

3. 3) Caloplaca emilii, newly described below, is closely related to the Mediterranean C. areolata. We consider C. emilii a Mediterranean species rarely occurring in higher latitudes in Austria, the Czech Republic and Germany. It is distinguished from C. areolata mainly by the presence of vegetative diaspores (blastidia); a possible role of blastidia in the distribution pattern of C. emilii is discussed below. Status of the names Caloplaca areolata, C. isidiigera and C. spalatensisis, formerly used for the new taxon, is clarified.

4. 4) Caloplaca molariformis, newly described below, belongs to the Pyrenodesmia group (a lineage of Caloplaca without anthraquinones). It is a continental species, frequently collected on limestone or lime-rich tuffs in steppes or deserts in Turkey, Iran, western Kazakhstan and southern Russia, and is also known from eastern Ukraine and southern Slovakia. Caloplaca molariformis is characterized by its thick thallus with fungal and algal tissues arranged in high stacks.

5. 5) Caloplaca substerilis, newly described below, is distinguished from the closely related C. ulcerosa by its endophloeodal or minutely squamulose thallus with soralia formed in bark crevices or on margins of squamules. While C. ulcerosa has a maritime distribution in Europe, C. substerilis is typically a continental species. North American continental lichens called “C. ulcerosa” are phylogenetically closer and more similar to C. substerilis.

The positions within Teloschistaceae of the taxa considered are demonstrated by ITS phylogenies. The distributions of C. areolata, C. emilii and C. interfulgens are mapped. The new species are fully described using more than a hundred phenotype characters, and diagnostic characters are indicated separately.

The resynthesis of foliose thalli of the cyanobacterial lichen Peltigera praetextata was achieved on a soil substratum under laboratory conditions. On agar plates mycelia formation by this lichen fungus only occurred when a sufficient number of photobiont cells was present. Resynthesis on agar was restricted to the formation of loose algal-fungal associations, which showed no lichen-like structures. Early resynthesis stages were formed on soil only after a very long lag phase of 2–3 months. First soredia-like stages (resynthesis products of fungal hyphae and cyanobacteria) appeared, later tissue clumps and thallus primordia differentiated. Welldeveloped lichen thalli with rhizines that resembled young thalli from the natural environment were formed after an incubation time of 2–3 years.

In this study we examined photobiont identity, diversity and selectivity in the genus Bryoria. We focused on B. fremontii and section Implexae in order to determine whether secondary chemistry is correlated with photobiont identity. DNA from two loci for photobionts and three loci for mycobionts was sequenced for both parsimony and Bayesian phylogenetic analyses. A comparison of photobiont and mycobiont phylogenies reveals that most Bryoria species associate exclusively with lineages of the Trebouxia simplex group; only B. smithii was associated with a different photobiont. We conclude that most Bryoria species included in our study are highly selective in their choice of algal partners and that the presence/concentration of different secondary compounds does not correlate with photobiont identity either in section Implexae or in B. fremontii.

A phylogenetic study using DNA sequences of the nuclear ribosomal large subunit from 38 species is used to infer the phylogeny of species currently placed in Topeliopsis. The genus is shown to be polyphyletic; monophyly of previous and current circumscriptions of the genus are rejected using two alternative hypothesis tests. Topeliopsis meridiensis is shown to be closer to Chapsa than Topeliopsis, but additional studies are necessary to understand the circumscription of Chapsa. The new genus Melanotopelia Lumbsch & Mangold is described to accommodate T. toensbergii and T. rugosa. These species were previously regarded as aberrant in Topeliopsis because of their thin-walled ascospores and dark pigmented proper exciple. The new combination Graphis mexicana (Hale) Kalb, Lücking & Lumbsch is proposed and Graphis muscicola and Topeliopsis globosa reduced to synonymy with this species.

A new method is described that records the periods of photosynthetic and respiratory activity in lichen thalli in situ by measuring the actinic chlorophyll fluorescence response of the photobiont. The technique is based on a pulse amplitude modulation fluorometer that was specially developed for continuous and unattended measurements in the Antarctic. In Livingston Island, South Shetland Islands, the periods of metabolic activity of Usnea antarctica were recorded simultaneously with the microclimatic parameter in its natural environment. In one series of diurnal measurements the fluorescence response signal was treated as a qualitative on/off signal for photosynthetic activity. In a parallel series the diurnal courses of net photosynthesis and dark respiration of rain-moistened thalli of U. antarctica were measured by means of a CO2/H2O porometer together with gravimetric water content determination. Both methods showed marked coincidence from low water content to water saturation of the thalli. In the laboratory both the actinic fluorescence response and the photosynthetic rate as a function of thallus water content were investigated in Caloplaca regalis. In the laboratory experiments the CO2 exchange cuvette contained a balance for gravimetric water content control as well as the glass-fibre optics of the fluorescence analysis equipment. The experiments revealed a quantitative relationship between actinic fluorescence and photosynthetic rate within the range of optimum to limiting low thallus water content. The method described is suitable for measurements of lichen activity in field microclimate studies and should allow continuous unattended year-round measurements of lichen activity, which are needed in remote regions such as Antarctica.

Classical hypotheses in lichenology predict pairs of species in which sexual lineages are ancestral and long-lived evolutionarily and that these give rise to derived, evolutionarily transient asexual lineages. Extensive phylogenetic information generated over the last 20 years regarding relationships within and among various groups of lichens makes possible an investigation of polarity and lability in reproductive mode across diverse clades. To test the long-held hypothesis of asexual reproduction as an evolutionary dead end in lichens, existing phylogenetic data from 23 studies were utilized to reconstruct gains and losses of sexual and asexual reproduction in a model-based statistical framework. Summed across all studies, between 26–44 origins of asexual reproduction from sexual ancestors (forward transitions) and 14–25 origins of sexual reproduction from asexual ancestors (reverse transitions) were identified. However, the higher number of gains of asexual reproduction was concentrated in a relatively low number of clades (e.g. Dirina). The greater number of forward compared to reverse transitions is consistent with dogma in both lichenology and evolutionary biology, but nonetheless this study documents numerous reverse transitions, suggesting that asexual lineages represent a source for evolutionary innovation.

The lichen genus Lepraria in Poland, comprising 17 species, is reviewed: for each taxon, remarks on the chemistry, distribution and habitat preferences are provided. Distribution maps are also presented, together with a key for determination of the Polish species. Lepraria diffusa var. chrysodetoides is reduced to a synonym of L. diffusa s. str., a new chemotype with a new substance is reported for L. neglecta, and rangiformic acid is reported for the first time for chemotype III of L. caesioalba. Lepraria borealis is reported for the first time from Africa (Canary Islands) and L. nigrocincta from Nepal.

The lichen Usnea longissima was used to examine how distance from forest edge and edge contrast influence growth of pendulous lichens. Thalli of two sizes (12 and 27 cm) were transplanted to the lower canopy of old Picea abies forest at 5, 25 and 100 m distance from cutovers. Sites represented three levels of edge contrast: high (clear-cut), intermediate (3 m tall saplings) and low (6–7 m tall young forest). Lichen growth was assessed as annual length and weight gain. Growth rates of intact thalli were size-dependent, with both growth variables being higher in long than in short thalli. Distance and edge contrast had significant effects on weight gain in long thalli but not in short ones. Weight gain in long thalli was twice as high near the edge (23%) compared to the forest interior (12%). The highest weight gain (31%) occurred at intermediate contrast edges with lower growth at both low (18%) and high contrast edges (20%). Chlorophyll a concentration was highest near the edge and positively correlated with weight gain, suggesting that growth was stimulated by both increased photosynthetic capacity and higher light availability near the edge. The lower part of the canopy in forest edges apparently have favourable growth conditions for U. longissima with growth being influenced by vegetation on adjoining cutovers. Therefore growth responses cannot explain the previously observed decline of pendulous lichens following edge creation. Our results suggest that vegetation buffers can improve conditions for pendulous lichens near forest edges.