Two new species of Pyxine with yellow medulla from saxicolous habitats are described as new to science. The new species P. punensis has an isidiate, UV+ yellow thallus with 0·3–0·6 mm wide lobes. Pyxine yercaudensis has smaller ascospores (13–16×6–7 µm), lacks vegetative propagules and lacks lichexanthone.

Pannaria minutiphylla Elvebakk and P. pulverulacea Elvebakk are described here as new to science. Both species belong to the panaustral P. sphinctrina (Mont.) Tuck. ex Hue complex. Their spores, however, are more long-ellipsoid and much less verrucose than those of P. sphinctrina itself, and the species are therefore not considered to be phyllidiate and sorediate counterparts, respectively, of the latter. Pannaria minutiphylla disperses with phyllidia, which are distinctly smaller and not as erect as those of a similar Australian species, P. phyllidiata Elvebakk. Pannaria pulverulacea has the smallest vegetative propagules within this species group. They are referred to as soredia here, although they are partly corticated. This species also has the widest distribution, including wet forests of southern South America, south-eastern Australia, and from Northland to Campbell Island in New Zealand. Pannaria minutiphylla has the same distribution and often grows together with P. pulverulacea, except in southern South America, where some related material has still not been sufficiently studied. Both species are very common within their distribution areas, and previously have mostly been identified as P. microphyllizans. The latter is, however, a very different species, which instead will be studied in comparison with P. athroophylla (Stirt.) Elvebakk & D. J. Galloway.

Niesslia echinoides Etayo, Flakus & Kukwa sp. nov. is described from Bolivia from the corticolous thallus of Erioderma barbellatum. The fungus is characterized by large ascospores usually breaking into halves within the asci, strongly setose and aggregated ascomata, usually simple setae, and no damage caused to the host thallus.

The article explains the current structure of Körber's herbarium, located in the Nationaal Herbarium Nederland, Leiden (L). Originally, Körber's herbarium was composed of two separate collections. One part, Koerber Typenherbar, represents well-developed samples of each species, but they are in fact often fragments of specimens from the main collection (Koerber Stammherbar). Several examples are presented which demonstrate the relationship between both parts of the collection, various origins of specimens in the Koerber Typenherbar and their importance for lectotypification. Some specimens in Körber's herbarium were labelled only with an abbreviation or a symbol instead of a locality. All abbreviations/symbols with their explanations, kept in the Leiden herbarium archive, are listed here with information on the current names of the sampling localities in Poland and the Czech Republic.

Over the last decades, levels of sulphur deposition from air pollution have been substantially reduced in Norway, whereas levels of nitrogen deposition have been stable or somewhat increased. In parallel, a clear trend of increasing annual temperatures, as well as precipitation, is evident. Human impact on natural ecosystems is predicted to reduce biodiversity at regional scales through facilitating a few generalist species at the expense of species with narrow habitat requirements. In this study, we investigate changes in community composition and the abundance of dominant lichen species on birch in subalpine forests over a 15-year period. The study is based on repeated measurements in five monitoring sites in Norway, representing regional gradients in temperature and precipitation as well as in deposition of nitrogen and sulphur compounds. Two dominant species are studied in particular; the generalist Hypogymnia physodes and the subalpine birch specialist Melanelia olivacea. The largest change in species composition was found in the site with the biggest reduction in sulphur deposition during the 15-year period, whereas the site with low precipitation and low pollution loads had small changes in species composition. The abundance of the generalist H. physodes increased in all sites and the specialist M. olivacea decreased in abundance, especially in sites with both high precipitation and heavy nitrogen deposition. Our study thus suggests that a warmer, humid climate is beneficial for the generalist H. physodes.

The vertical gradient of the community structure of epiphytic lichens in forest canopies was studied in southern Estonian coniferous forests. All lichen species on 15 Norway spruces and 15 Scots pines were recorded; age of trees ≥100 years. Species were sampled in height ranges on entire trees from the bottom to the top. The number of lichen species on pine trunks decreased with height from the ground, whereas the number of species on branches increased. There was no significant vertical change in the number of lichen species on spruce trunks; number of species on spruce branches was highest in mid canopy. The mean number of lichen species on a tree was 41 in spruces and 34 in pines; the mean number of species on the first 2 m was 14 in spruces and 12 in pines. According to the results, about two thirds of a tree's lichen species remain unrecorded if only the first 2 m near the ground are surveyed. Many lichen species were found only higher than 2 m, including several common species (e.g. Buellia griseovirens, Lecanora pulicaris, and Melanohalea exasperatula), but also some locally rather rare (Fellhanera subtilis, Micarea nitschkeana, Rinodina efflorescens) or red-listed ones (Evernia mesomorpha, Usnea barbata, U. fulvoreagens, U. substerilis, U. wasmuthii) and one new species for Estonia, Lecanora farinaria. There were also some species, such as Chaenotheca stemonea, Cladonia cenotea and C. norvegica, that were restricted to the lowest 2 m. The results indicate that canopy lichens form a significant part of lichen diversity in coniferous forests, and could add valuable information when estimating forest lichen diversity for conservation and other purposes.

The widespread and ubiquitous lichen-forming fungus Protoparmeliopsis muralis is able to form a thallus with Trebouxia species. In this study, several photobiont strains were isolated from different specimens of P. muralis and cultured in vitro. The compatibility of Trebouxia spp. and Asterochloris algae with P. muralis were investigated in in vitro resynthesis experiments and the re-lichenized bionts were observed with the scanning electron microscope. It was found that, in addition to compatible photobionts, also a presumably incompatible Asterochloris sp. was able to interact with the mycobiont. The life strategy that enables the mycobiont to form associations with a wider range of photobionts could be advantageous for the survival of the lichen and successful colonization of new habitats.

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.

The epiphytic lichen Evernia prunastri is sensitive to air pollution and reacted by total retreat to the worsening of air quality during the peak of SO2 pollution in Central Europe (1950s–1990). Since 1990, after a significant decrease in air pollution, epiphytic lichens recolonized previously polluted areas, including E. prunastri. We investigated the physiological status of E. prunastri, transplanted for six months in 34 sites in the urban area of Bratislava (Slovakia) under current conditions. The content of chlorophylls, cortical and medullar secondary metabolites and soluble proteins were explored. We then examined the relationship of these parameters with the environmental quality status, reflected by the diversity of epiphytic lichens. The results showed that the physiological status of E. prunastri did not change significantly after exposure. Positive correlations were found between lichen diversity in the sampling sites and physiological parameters (photosynthetic pigments and phaeophytinization quotient) in the transplants. Transplants from sampling sites with a greater proportion of nitrophilous lichens displayed a decrease in photosynthetic pigments. Sites where E. prunastri naturally occurred had a lower proportion of nitrophilous species in comparison to sites where E. prunastri was not present. This suggests that the indicator species E. prunastri may also recolonize sites with low eutrophication in urban environments under decreased air pollution, and the information on its presence can help to assess the pressure caused by nitrogen excess.

The effects of hydrogen sulphide (H2S) on five lichens with different photobionts, ecology, and tolerance to the pollutant were studied by means of samples exposed in closed chambers containing two known H2S solutions. The H2S concentration in the void volume at equilibrium with the liquid phase was measured by gas chromatography-mass spectrometry, combined with the use of solid phase micro extraction (GC/MS SPME). It was determined as 8 and 28 ppm H2S in the absence of lichen material, and c. 2 and 10 ppm H2S respectively with living lichen material inserted for 8 hours in the exposure chambers. Significant differences in the species-specific emission of chlorophyll a fluorescence (ChlaF) were observed, with a pronounced depression of Fv/Fm already detectable after 2 h exposure at 28 ppm H2S in all the species. The decreased intensity was positively correlated to sample surface and, to a lesser extent, to the species-specific pre-exposure Fv/Fm value. Dark-exposed samples were less affected than light-exposed ones. All four chlorolichens could recover the pre-exposure ChlaF emission after two days in the absence of H2S, both in the light and in the dark, whereas the cyanolichen did not recover when kept in the dark. The results are thoroughly discussed on the basis of the known action mechanisms of H2S on the photosynthetic apparatus of vascular plants and cyanobacteria.

Some lichens that occur in mountains and arid regions have developed an unusual anatomy resembling window-leaved plants. In these lichens, algal cells occur in thick vertical stacks (algal stacks) separated by vertical channels of light-transferring fungal hyphae (fungal stacks). We present experimental evidence that this anatomy permits higher rates of area-based CO2 assimilation in strong light, but that it also leads to higher respiration resulting in higher compensation irradiance. The net effect of this anatomy must be beneficial in regions of high insolation, as it has arisen many times in different parts of the world, and in unrelated lichens, and these lichens often dominate the communities in which they occur.