The influence of environmental variables on epiphytic lichens in Liguria (NW Italy) was examined using two complementary approaches. Firstly, the variability of lichen vegetation in relation to environmental variables was investigated. Secondly, the variability of Lichen Biodiversity (LB) counts, used in biomonitoring studies, was analysed in relation to bioclimatic areas. Geomorphology strongly affects lichen vegetation. The coastal mountain ridge and the Tyrrhenian-Po valley watershed limit the distribution range of three different communities: a Parmelion community with a high frequency of coastal suboceanic species, a Parmelion community rich in oak wood species and the Pannelietum acetabuli association, situated beyond the Po Valley watershed. Substantial differences in the distribution of lichen communities related to a climatic gradient (from humid Mediterranean to dry sub-Mediterranean regions) are not matched by corresponding statistically significant differences in LB counts. More accurate studies are necessary to define homogeneous bioclimatic areas, in which LB values can be compared for biomonitoring purposes.

Floristic, vegetational and ecological features of lichens in ultramafic environments are reviewed using a wide range of literature dating from the beginning of the 20th century. Co-presence of acidophytic (silicicolous) and basiphytic (calcicolous) species and the occurrence of species characterized by particular (disjunct) distribution patterns are features of lichens in ultramafic environments. It is not possible to detect consistent trends in data on other broadly accepted features, such as paucity of species, low cover and the occurrence of particular ecotypes because of the influence of several environmental factors in addition to the substratum. Some recent data about physico-chemical interactions between saxicolous lichens and ultramafic rocks are also reported.

The study aimed to optimize culture conditions and nutrient requirements for theproduction of secondary metabolites by the cultured mycobiont Lobaria spathulata. This species proved to be an excellent model system for such studies, as the complete chemosyndromefound in the natural lichen thallus was repeatedly formed in the cultured mycobiont with differentiated, aerial mycelia. Nutrient media containing the disaccharide, sucrose, were found to favour both rapid growth and the production of typical lichen substances. Higher proportions of the secondary compounds were detected in the developing mycobiont than in mature lichen thalli.

Cephalodia were investigated on young and mature thalli of Lobaria pulmonaria. Cephalodia originate from contact between hyphae and cyanobacteria on the upper or lower cortex or, less frequently, in the apical zone. Young thalli were found to associate with cyanobacteria even in the anchoring zone. Cephalodia formed on the young thalli or the anchoring hyphae share the same phenotypic characteristics. In spite of being composed of paraplectenchymatous hyphae, the cortex of mature thalli preserves a considerable plasticity, enabling the formation of cephalodia. The cyanobacterial incorporation process begins with cortical hyphae growing out towards adjacent cyanobacterial colonies, enveloping them and incorporating them into the thallus. The incorporation process is the same on the upper and the lower cortex. Early stages of cephalodia are usually found in young lobes, whereas in the older parts of the thallus only mature cephalodia are found.

Alectorioid and foliose lichens were weighed from full-size branches of Picea abies cut at two canopy heights in 100 trees in an old subalpine forested area in eastern Norway. The mean lichen biomass per branch decreased from 46 to 37 g moving upwards from 2–3 to 5–6 m canopy height. The lichen biomass correlated strongly with branch size variables, branch diameter alone explaining 48 of the variation in lichen biomass per branch (n=200). The alectorioid/foliose biomass ratio increased from 0·149 at 2–3 m to 0·316 at 5–6 m. Site factors reflecting openness of the canopy were computed for the branch at 2–3 m in all trees. The alectorioid/foliose biomass ratio increased significantly with the indirect site factors, suggesting that light, or factors associated with light, determine the balance between these two growth forms in tree canopies. Within the alectorioid biomass component, genera with usnic acid (Alectoria, Usnea) decreased with height, whereas the genus Bryoria with melanic pigments increased. According to the literature, dark melanic pigments have higher visible light screening efficiency than the yellowish usnic acid. Such patterns suggest a functional role for cortical pigments in the niche differentiation of alectorioid lichens.

Genetic diversity in symbionts of the lichen Cladonia arbuscula was investigated. Forty-eight specimens of Cladonia arbuscula located within a 2 km range at Payuk Lake in Manitoba were collected. Population structure and method of symbiont transmission in C. arbuscula were inferred by examining the presence or absence of introns in the nuclear small subunit (SSU) ribosomal DNA (rDNA) of the mycobiont and restriction fragment length polymorphism (RFLP) of the internal transcribed spacer (ITS) rDNA in the photobiont. The mycobiont showed a high level of genetic variation and the photobiont a low level of variation within the small geographic range studied. An analysis of molecular variance of fungal genotypes showed significant population subdivision for the mycobiont when the data were analysed at P=0·05. No population subdivision was detected when P=0·001. The photobiont also showed no population subdivision. Photobiont genotypes did not correlate with mycobiont genotypes suggesting the symbionts were not transmitted together in the same propagule. Multiple fungal genotypes were also detected in C. arbuscula and possible explanations were discussed.

The distribution of lichen species in upland regions of Aberdeenshire, Scotland, is investigated along a landuse gradient from natural forest to intensive agriculture. Quantitative data on lichen communities on saxicolous, epiphytic and terricolous substrata were collected from 16 hectares in one km2 in each landuse type. Multivariate analyses, NMDS and Cluster analysis were used to identify lichen communities associated with environmental factors including landuse, substratum type and age. The epiphytic community of native pinewoods was distinguished from all others by the highest species richness, the presence of indicators of ecological continuity and the absence of nitrophytes, while the epiphytic communities of farmland were distinguished by absence of acidophytes and a high contribution of nitrophytes. Plantations of conifers were distinguished by low species richness and an increase in tolerant species. Saxicolous communities were frequent on walls in all sites except native pinewood, where saxicolous substrata were rare. Intensively farmed sites were distinguished by an increase in percentage contribution of nitrophytes. The high acidophyte contribution in all sites suggests that crustose species of acid rocks may not respond rapidly to an increase in applied nitrogen. In landscapes where tree cover is sparse or non-existent combined assessment of habitat diversity and nitrophyte indicator species can be used to assess changes associated with agricultural intensification.

Lichens were cultured by attaching a thallus fragment to a nylon monofilament loop with silicone sealer. Two effective methods for adjusting lichen mass to a standard moisture content were developed (the ‘reference-sample’ and ‘sacrificial’ methods). These corrections for moisture content allow detection of very small changes in dry mass without having to oven dry (and kill) all transplants. Average annual biomass growth rates for non-fragmenting species were typically between 5 and 30%. Annual biomass growth rates of healthy, vigorous individuals, as indicated by the 75th percentile, were mostly between 10 and 40%. Alectoria sarmentosa was prone to fragmentation despite the maintenance of healthy thalli. The other species can be ranked by biomass growth rates as follows: Evernia prunastri> Lobaria pulmonaria=Usnea longissima> Pseudocyphellaria rainierensis=Lobaria oregano.

Lichen communities at four sites of copper sulphide mineralization and associated secondary oxidation products are described from an old mining area at Coniston in the English Lake District. Five lichen species new to Britain, Stereocaulon symphycheilum, Lecanora handelii, Rhizocarpon furfurosum, Lecidea atrofulva and L. inops, are briefly described, the last mentioned being a specific indicator of copper mineralization. The species complex, Lecidea auriculata, L. diducens and L. inops, is discussed in some detail. Toninia leucophaeopsis and the non- British Bilimbia tornensis are distinct species and are both referred to the genus Stereocaulon.

The green algal photobionts of 12 Xanthoria, seven Xanthomendoza, two Teloschistes species and Josefpoeltia parva (all Teloschistaceae) were analyzed. Xanthoria parietina was sampled on four continents. More than 300 photobiont isolates were brought into sterile culture. The nuclear ribosomal internal transcribed spacer region (nrITS; 101 sequences) and the large subunit of the RuBiSco gene (rbcL; 54 sequences) of either whole lichen DNA or photobiont isolates were phylogenetically analyzed. ITS and rbcL phylogenies were congruent, although some subclades had low bootstrap support. Trebouxia arboricola,T. decolorans and closely related, unnamed Trebouxia species, all belonging to clade A, were found as photobionts of Xanthoria species. Xanthomendoza species associated with either T. decolorans (clade A), T. impressa, T. gelatinosa (clade I) or with an unnamed Trebouxia species. Trebouxia gelatinosa genotypes (clade I) were the photobionts of Teloschistes chrysophthalmus,T. hosseusianus and Josefpoeltia parva. Only weak correlations between distribution patterns of algal genotypes and environmental conditions or geographical location were observed.

Biological crusts are a common feature of the soil surface in arid and semi-arid ecosystems, where they play a major role in ecosystem functioning. In recent years, there has been an increasing interest in the ecophysiology, floristics, and dynamics of crust-forming lichens but little is known about the effect of vascular plants on their small-scale spatial distribution. To increase our understanding about the interactions between crust-forming lichens and vegetation in semi-arid areas, the spatial pattern and interaction of two soil lichens, Cladonia convoluta and Squamarina cartilaginea, at two microsites in semi-arid Stipa tenacissima steppe of south-eastern Spain are evaluated. The aim of this study was to determine if the microsite provided by Stipa tussocks promoted changes in the individual patterns and in the spatial covariation of these soil lichens. Spatial analysis by distance index (SADIE) coupled with correlation analysis was used to explore the individual patterns and the spatial relationships between the two species. SADIE detected a significant clumped pattern in the spatial distribution of both species, but Stipa tussocks promoted changes only in the spatial pattern of Cladonia. Correlation analysis revealed the presence of significant relationships between the two species, particularly close to Stipa tussocks. The results show that the microenvironment provided by Stipa is able to modify the small-scale spatial pattern of soil lichens in semi-arid steppe, and suggest the presence of facilitation between Stipa and Cladonia.

The family Stictidaceae (Ostropales, Ascomycota) contains both lichenized and non-lichenized fungi. Here, we test if Conotrema (lichenized) and Stictis (non-lichenized) as currently delimited are distinct monophyletic genera, by parsimony and parsimony jackknifing analyses of combined nuclear rDNA (ITS and partial LSU rDNA) and mitochondrial SSU rDNA sequence data matrices. The study includes four species of Stictis, three species of Conotrema, and representatives of the related Schizoxylon (lichenized), Odontotrema, Carestiella (at least sometimes associated with algae), Cryptodiscus and Thelotrema (lichenized). In all analyses, the Conotrema species were nested within Stictis with high support. Thus, we conclude that Conotrema are only lichenized representatives of Stictis. The type species of the two generic names, C. urceolatum and S. radiata, are sister taxa in our analyses. Furthermore, the analysis gave no support for the present infrageneric classification of Stictis. Carestiella socia (the type of Carestiella) and the two representatives of Schizoxylon studied were also nested within Stictis s. lat. The Odontotremataceae is the sister group to the Stictidaceae, and Cryptodiscus foveolaris groups with Thelotrema rather than with the Stictidaceae. We conclude that lichenization in the Stictidaceae does not characterize natural groups, and that Conotrema should be considered a synonym to Stictis, as predicted by anatomical characteristics. The new combinations Stictis urceolatum and Stictis populorum are made.

We provide an expanded and updated, 2-locus phylogeny (mtSSU, nuLSU) of the lichenized fungal family Trypetheliaceae, with a total of 196 ingroup OTUs, in order to further refine generic delimitations and species concepts in this family. As a result, the following 15 clades are recognized as separate genera, including five newly established genera: Aptrootia, Architrypethelium, Astrothelium (including the bulk of corticate species with astrothelioid ascospores; synonyms: Campylothelium, Cryptothelium, Laurera), Bathelium s. str. (excluding B. degenerans and relatives which fall into Astrothelium), the reinstated Bogoriella (for tropical, lichenized species previously placed in Mycomicrothelia), Constrictolumina gen. nov. (for tropical, lichenized species of Arthopyrenia), Dictyomeridium gen. nov. (for a subgroup of species with muriform ascospores previously placed in Polymeridium), Julella (provisionally, as the type species remains unsequenced), Marcelaria (Laurera purpurina complex), Nigrovothelium gen. nov. (for the Trypethelium tropicum group), Novomicrothelia gen. nov. (for an additional species previously placed in Mycomicrothelia), Polymeridium s. str., Pseudopyrenula, Trypethelium s. str. (T. eluteriae group), and Viridothelium gen. nov. (for the Trypethelium virens group). All recognized genera are phenotypically characterized and a discussion on the evolution of phenotypic features in the family is given. Based on the obtained phylogeny, species delimitations are revised and the importance of characters such as thallus morphology, hymenial inspersion, and secondary chemistry for taxonomic purposes is discussed, resulting in a refined species concept.

Cladonia rei and Cladonia subulata are morphologically similar, but chemically different cup lichens of dry grasslands and nutrient-poor ruderal habitats. Recently, C. rei has been synonymized with C. subulata on the basis of combined morphological and chemical investigations. However, doubts remained due to a molecular divergent North American sample of C. rei compared to European C. subulata. To clarify the situation, using molecular methods, we analysed chemically different European samples of C. rei and C. subulata, as well as other morphologically or chemically similar Cladonia species. Molecular data show that European and North American samples of C. rei belong to the same clade, which is closely related to C. fimbriata and followed by a subclade with C. coniocraea and C. ochrochlora. The subclade of C. subulata appears to be distinct from C. rei. In concordance with molecular data, the presence of homosekikaic acid is the determining chemical feature for C. rei. In addition, C. humilis and C. innominata proved to be molecularly distinct species.

Usnea longissima was sampled in SE Norway on six main branches of one Picea abies, comprising its full vertical canopy range. Nearly all specimens (n = 781) were unattached and fragmented, in contrast with associated lichens. A combination of weak axes and lack of holdfasts resulted in a population of repeatedly displaced thalli, a similar situation as in ground-dwelling vagant lichens. Comparisons with a litterfall population indicated that thalli, regardless of size, had a similar probability to end as litter on the ground. Specimens were frequently sorediate, but only 12 small thalli with a basal holdfast had been directly recruited through soredial establishment. Its patchy distribution within apparently homogenous forest stands is probably a consequence of a rare successful long-range dispersal through soredia coupled with an abundant local dispersal of coarse thallus fragments. Old forests with ample, diffuse skylight at lower and humid canopy levels are probably essential to maintain a vagant epiphytic life form with a predominantly downward dispersal of thallus fragments.

Rinodina is a widespread, polyphyletic genus of crustose Physciaceae with c. 300 species worldwide. A major missing link in understanding its global biogeography has been eastern Asia where the genus has never been systematically revised. Here we review specimen and literature records for Rinodina for north-eastern Asia (Russian Far East, Japan and the Korean Peninsula) and recognize 43 species. We describe two species, R. hypobadia and R. orientalis, as new to science. Rinodina hypobadia is distinguished by its pigmented hypothecium, Dirinaria-type ascospores and pannarin in both thallus and epihymenium. Rinodina orientalis is characterized by its erumpent apothecia that remain broadly attached, with discs sometimes becoming convex and excluding the thalline margins, ascospores belonging to the Physcia-type and secondary metabolites absent. Nine other species are reported from the region for the first time. These include R. dolichospora, R. freyi, R. metaboliza, R. sicula, R. subminuta and R. willeyi. Of particular biogeographical interest are three additional new records that have western North American–eastern Asian distributions: the corticolous species R. endospora, R. macrospora and R. megistospora. Six species have the better known eastern North American–eastern Asian distributions: R. ascociscana (syn. R. akagiensis, R. melancholica), R. buckii, R. chrysidiata, R. subminuta, R. tenuis (syn. R. adirondackii) and R. willeyi, and two have eastern North American–eastern Asian–European distributions: R. excrescens and R. moziana (syn. R. destituta, R. vezdae). Our study begins to close one of the largest gaps in our knowledge of circumboreal species distributions in Rinodina and, together with previous studies in North America and Europe, provides new insights into circumboreal crustose lichen biogeography. Rinodina cinereovirens (syn. R. turfacea var. cinereovirens) is also reported as new to North America.

Thalli of Lobaria pulmonaria of different sizes were collected from the trunks of two specimens of Populus tremula. The secondary lichen compounds, stictic, constictic, norstictic, peristictic, cryptostictic and methyl stictic acid were quantified by HPLC and ranked in order of decreasing concentration. There was a highly significant positive correlation between thallus size and the total concentration of secondary compounds, as well as the total content per unit area for specimens from the two sampled trees. According to hypotheses inferring a herbivore deterrent role of secondary lichen compounds, small, juvenile thalli should be more susceptible to herbivores than larger thalli. Thus herbivory might limit survival of young specimens in habitats rich in lichen-feeding molluscs and thereby reduce reproductive success.