Ramalina europaea Gasparyan, Sipman & Lücking and R. labiosorediata Gasparyan, Sipman & Lücking, two species of the R. pollinaria group, are described here as new to science. Ramalina europaea, widely distributed in Europe, can be distinguished by small, punctiform, often terminal soralia starting out on small, spine-like branchlets, whereas R. labiosorediata from North America differs from R. pollinaria s. str. and R. europaea in the almost exclusively terminal soralia formed on the tips of normal lobes, originating from the underside and becoming irregularly labriform. Morphological characters, chemistry, ecology and geographical distribution are discussed and a key to the species of the Ramalina pollinaria group is provided. The topology of a maximum likelihood tree based on ITS shows the presence of three well-supported clades, corresponding to the morphological differences of the three species. The status of several historical names variously placed in synonymy with or described as infraspecific entities of R. pollinaria is reassessed and a new neotype and an epitype are designated for Lichen pollinarius, a neotype for L. squarrosus, making it a synonym of R. farinacea, and lectotypes for R. pollinaria var. elatior, making it a synonym of R. pollinaria s. str., and for var. humilis, a taxon of yet unknown affinity.

The rate of lobe division during thallus enlargement in Xanthoria elegans and Diploicia canescens is considered in geometric terms. The frequency of lobe engulfment by neighbouring lobes was measured, was fitted graphically to a simple equation and was found to result from constant lobe division with thallus size. Values for a constant in the equation and derived from the observed frequency of lobe engulfment provided a measurement of a new morphological parameter: ratio lobe length to width. Greatest departure from circularity in small thalli of D. canescens occurred when thallus size did not permit lobe competition. Increasing lobe engulfment and thallus circularity in larger thalli appeared to be correlated. Circularity in crustose thalli without lobes is discussed with definitions of ‘primary’ and ‘secondary’ areoles.

On the basis of light microscopic (LM), scanning electron microscopic (SEM) and transmission electron microscopic (TEM) investigations the Pertusaria-type of ascus is described as a particular functional type. The functionally unitunicate Pertusaria-type is characterized by its structure, staining properties, and by its particular mode of dehiscence. Tripartite ascus walls were observed in LM and TEM. The non-amyloid ascus wall is surrounded by a thin, amyloid outer layer. Both become amorphous at maturity and partly disintegrate. An apically thickened, amyloid inner layer reaches the base of the ascus. In its fine structure this amyloid inner layer resembles the material of the amyloid dome of Lecanora-type asci. It plays an important role during dehiscence and spore discharge. An elongation process was observed prior to dehiscence, at the end of which the ascus tip is situated above the hymenial surface. Dehiscence occurs by bursting or splitting of the whole ascus tip. The Pertusaria-type might represent a side-branch of evolution from bitunicate to unitunicate forms within the Lecanorales.

Pertusaria-type asci are restricted to a small number of genera within the Pertusariaceae. A considerable heterogeneity in ascus structure and staining properties was observed within the Pertusariineae sensu Henssen & Jahns (1973) and Henssen (1976).

Lecanora demissa (Körb.) Zahlbr. is a crustose, lobate lichen that produces soredia and conidiomata but no apothecia. Its placement in Lecanora has long been questioned but nothing better has been proposed. We have studied the nuclear rDNA of the ITS regions and the SSU of L. demissa. In an alignment of the ITS regions of several representatives of Lecanora s. lat. it could clearly be shown by a PAUP analysis, using Aspicilia caesiocinerea as outgroup, that L. demissa does not belong to Lecanora. In a PAUP analysis of sequences of the SSU from representatives of the order Lecanorales, using members of Saccharomycetales as outgroup, L. demissa clustered on a well-supported branch with Caloplaca chlorina. In a further analysis of the ITS sequences of L. demissa together with representatives of Caloplaca and Xanthoria using Protoparmelia as outgroup two most parsimonious trees were found. In these trees the L. demissa branch was well within a strongly supported clade with C. cerina, the type species of the genus Caloplaca. The sister taxon to L. demissa in this analysis was C. variabilis. Chemical data and characters of the conidiomata support the affinity with Caloplaca and the new combination C. demissa (Körb.) Arup & Grube is therefore proposed. A lectotype for Imbricaria demissa has been designated. The phylogenetic analysis of several representatives of the genera Caloplaca and Xanthoria suggests that these genera are not monophyletic as presently circumscribed. Two large, monophyletic groups of species could be recognized, one with Xanthoria species mixed with lobate and crustose members of Caloplaca, and one with mainly crustose Caloplaca, including both species with orange or black apothecia.

The distribution of cryptogams and phanerogams and the microclimate of different habitats have been studied. It is shown that a forest community of phanerogams includes an assemblage of different microhabitats inhabited by different lichens and mosses. The distribution of lichens and mosses is governed by factors that are often of little importance to higher plants.

Umbilicaria iberica and U. maculata are described as new to science on the basis of morphological and molecular data. Umbilicaria iberica is similar to U. polyphylla but differs in having a monophyllous thallus with a distinctive white reticular pattern over the umbilicus and actinodisc apothecia. Umbilicaria maculata is similar to U. cylindrica but this new species is distinguished by its grey-brown thallus with sparse marginal cilia and white stains on the upper surface especially in the marginal zone, as well as by sessile apothecia with one or a few sterile fissures. Nuclear ITS and LSU rDNA have been used as molecular markers. In the phylogenetic analysis U. polyphylla falls into two well supported clades (A and B), one of which corresponds to the morphotype that is described here as a new taxon. Specimens previously recognized as U.cylindrica fall into three well supported clades: clade C corresponds to the typical morphotype, clade D corresponds to morphotype II described here as a new taxon, and clade E is morphotype III which is recognized as U. cf. umbilicarioides. Typical group I introns have been found in position 1506 of the nuclear SSU rDNA of Umbilicaria; a consensus secondary structure of these introns is presented and we conclude that they represent an important and valuable molecular marker which gives additional support to the ITS and LSU sequence phylogeny obtained.

Detailed anatomical and chemical studies conducted on recent collections made in almost all suitable habitats on Réunion, a small remote tropical island in the Indian Ocean, yielded a surprising diversity in the widespread lichen genus Micarea (Pilocarpaceae, Lecanorales). Twenty-one species are recognized, including 13 described here as new to science. They are: Micarea alectorialica, M. bebourensis, M. borbonica, M. boryana, M. cilaoensis, M. hyalinoxanthonica, M. isidiosa, M. melanoprasina, M. pseudocoppinsii, M. pseudolignaria, M. sublithinella, M. takamakae and M. tenuispora. Notes on local ecology and important biogeographical features are also given and a key to the species is provided. Isidiiform areolae are reported for the first time in the genus (M. isidiosa and M. tenuispora), as well as the production of protolichesterinic and confluentic acids (M. sublithinella and M. takamakae, respectively). Two groups within the genus are species-rich on the island: the M. peliocarpa group with possibly 5 species, including 3 new to science, and the M. prasina group with 4 species, including 2 new to science. Micarea levicula is reported here for the first time since its description, and the status of the material that can be referred to M. micrococca s. lat. needs further study.

Lobaria pulmonaria is an epiphytic lichen that, in south-eastern Canada, inhabits deciduous forests where it must acclimate to large seasonal changes in temperature and in light caused by closing and opening of the leaf canopy. On a seasonal timescale, this acclimation occurs via large shifts in the macromolecular complexes of the photosynthetic system, within a photobiont population that shows no seasonal change in cell numbers. In this study, samples of L. pulmonaria were harvested in February and in May from a natural population near Sackville, New Brunswick, and subjected to two simulated intense seasonal changes: (1) early spring warming, simulated by a shift from high light at 5°C to high light at 16°C (February shift), and (2) late spring canopy closure, simulated by a shift from high light at 16°C to low light at 16°C (May shift). Thallus samples were collected daily throughout each week-long shift. There were no significant changes in photobiont cell population size or in the fraction of cells dividing during either shift. During the first day of the February temperature shift, there were, however, large changes in the pools of chlorophyll, the major light capture molecule in the photobionts, the PsbA (D1) core protein of photosystem II whose turnover is highly responsive to changing light and temperature, and the RbcL major subunit of the carbon-fixing RUBISCO enzyme whose levels correlate strongly with achieved photosynthesis in lichens. A static population of photobionts was therefore able to perform large and rapid macromolecular reallocations to cope with rapid environmental change. No significant changes were seen in the chlorophyll, photosystem II or RUBISCO pools across the May light shift, although seasonal-scale macromolecular reallocation does occur in response to decreased light in the summer.

135 infrageneric taxa of epiphytic lichen were found in 20 stands of tree-line forests of the Central-Eastern Italian Alps. Three forest types were considered: (1) late successional stands with several large trees, (2) pioneer stands on abandoned pastures without large trees, and (3) open and grazed stands. They were compared on the basis of four main criteria: (1) species richness, (2) number of rare species, (3) number of species that are exclusive to the subalpine belt in Italy, and (4) number of species that are exclusive to the Alps in Italy. Species richness is higher in the late successional stands, which also host a higher share of rare and exclusive species. The total number of rare species per site is correlated with the total number of species, as well as with the number of common species, and with the total number of macrolichens. Rare macrolichens are correlated with common macrolichens. Two main groups of target species with decreasing conservation priority are identified. Letharia vulpina is suggested as signal species for sites worthy of conservation. The guild of macrolichens may be used as an indicator of both species richness and of the occurrence of rare species.

Spilonema was originally described to accommodate an unusual group of cyanolichens with thread-like, cushion-forming thalli, and has long been placed in Coccocarpiaceae based on ascomatal development. However, Spilonema is the only genus of Peltigerales to include species lichenized with the cyanobacterial genus Stigonema, and the evolutionary relationships of Spilonema to other genera in the family have yet to be tested using molecular data. We present evidence from combined nuclear 28S, 18S and mitochondrial 12S rDNA to confirm the placement of the core species of Spilonema (S. paradoxum and S. revertens) in Coccocarpiaceae. Our data further show that despite possessing a different genus of photobiont (Scytonema), the north Pacific endemic genus Spilonemella must be included within Spilonema, suggesting that closely related species of the genus have changed photobionts in the course of evolution. However, we recovered Spilonema dendroides, one of the only lichens known to associate with the cyanobacterial genus Hyphomorpha, as only distantly related to the Coccocarpiaceae. The evolutionary relationships of this species are as yet unclear but it may occupy a basal position in the Peltigerales. We create for this species the new genus Erinacellus T. Sprib., Muggia & Tønsberg.

Tetramelas phaeophysciae, a new obligately lichenicolous species occurring in Scandinavia, Iceland and Greenland, is described, and the closely related Buellia pulverulenta, together with B. triphragmioides, are transferred to Tetramelas. Phylogenetic reconstructions based on sequence data from nITS1-5.8S-ITS2 rDNA, using Bayesian inference and parsimony analyses, support the segregation of the new species from B. pulverulenta as well as the segregation of Tetramelas and Diplotomma from Buellia s. str.

The influence on uptake and water loss of the structural changes experienced by Parmelia acetabulum during thallus development were investigated. Small specimens were characterized by flat lobes and a thin thallus and cortex. Large specimens appeared strongly rugose, imbricate and irregularly folded, and had a significantly thicker cortex and medulla than small thalli. Maximum water storage capacity did not differ between large and small thalli, although water retention was much higher in large thalli, presumably due to the interaction of structural characteristics and a higher boundary layer resistance. This translated into a longer duration of the period of thallus hydration in large thalli compared to small thalli. Incubation of thalli in water-vapour-saturated atmospheres induced full recovery of photosynthetic electron transport to the values before desiccation in small thalli but only induced a partial recovery in large thalli. The close correlation between photosynthetic electron transport and net photosynthesis during desiccation found in this species suggested that carbon-fixation activity could be regained to a larger extent by incubation of thalli in water vapour in small compared to large thalli. The higher ability for water vapour uptake of small thalli might allow them to efficiently use small amounts of intermittently available water or periods of high relative humidity. The significance of this differential ability to utilize water is discussed with regard to the known ecological preferences of the species.

As part of an ongoing inventory of the lichenized mycota of the Caxiuanã National Forest, at Ferreira Penna Research Station in the Brazilian Amazon, two species of lichenized fungi are described as new and four new combinations are introduced: Ampliotrema megalostoma (Müll. Arg.) M. Cáceres & Lücking comb. nov., Graphis brachylirellata M. Cáceres & Lücking sp. nov., Malmidea leucogranifera M. Cáceres & Lücking sp. nov., Ocellularia conformalis (Kremp.) M. Cáceres & Lücking comb. nov., Redingeria microspora (Zahlbr.) M. Cáceres & Lücking comb. nov., and Sarcographa megistocarpa (Leight.) M. Cáceres & Lücking comb. nov.

Bryoria pseudocapillaris and B. spiralifera are currently treated as members of Bryoria section Implexae although conspicuous, long and depressed pseudocyphellae characterizing both species resemble those found in the genus Sulcaria. Both genera belong in Parmeliaceae and form an alectorioid group together with Alectoria, Gowardia and Pseudephebe. Parsimony and Bayesian analyses of ITS, partial GAPDH and partial Mcm7 sequence data were used to examine the phylogenetic position of B. pseudocapillaris and B. spiralifera, and in light of these results evaluate the generic delimitation of Bryoria and Sulcaria. A total of 110 specimens of 53 species containing representatives from alectorioid and closely related genera were included in the analyses. The results clearly show first, that both B. pseudocapillaris and B. spiralifera belong in Sulcaria rather than in Bryoria, and second, that they should be considered conspecific. Bryoria pseudocapillaris is proposed as a synonym under B. spiralifera and the name Sulcaria spiralifera comb. nov. is introduced.

Chlorophyll a fluorescence is often used to estimate various types of damage in lichens. In order to optimize the output and improve interpretations of such measurements the protocol for pretreatment and measuring is important. To study the effects of measurement conditions, the lichens Lobaria pulmonaria, L. scrobiculata, Xanthoria parietina and Parmelia sulcata were first stressed by high light intensities at 600 or 1000 µmol photons m−2 s−1 for 4 h. Then various conditions during recovery or pretreatment were used to optimize the detection of more lasting damage. Recovery from photoinhibition was incomplete in darkness, whereas light as low as 0·2 or 1·0 µmol m−2 s−1 resulted in complete recovery if the recovery period was long enough. Additionally, low intensity light given for1·5 h after one day in darkness caused rapid and complete recovery. In conclusion, before measuring maximal PSII efficiency (Fv/Fm) with chlorophyll fluorescence, it is important to let lichens recover in low intensity light and not in darkness, to optimize recovery from photoinhibition; dark adaptation can only be recommended if the photoinhibition status of the lichens is of interest.

Reports of ‘Psoroma sphinctrinum’ from Palaeotropical areas are shown to represent instead species of the genus Gibbosporina, which is described here as new to science. This genus is superficially similar to tripartite, austral Pannaria species, such as the species now referred to as Pannaria sphinctrina (Mont.) Tuck. ex Hue. A phylogram based on an analysis of the nuclear large subunit rDNA (LSU) locus shows that Gibbosporina is instead a clade in a Pannariaceae branch referred to as the ‘Physma group’, a most unexpected addition to Pannariaceae dealt with by several previous studies. Genera assigned to this group have very contrasting general appearances. However, this diverse group shares distinctly ring-like thalline excipular margins; strongly amyloid internal ascus structures; well-developed perispores which have irregular gibbae and/or nodulose or acuminate apical extensions, but not verrucae; lacks TLC-detectable secondary compounds and have tropical distributions. Gibbosporina is the only tripartite genus in the group, with distinct, nodulose, placodioid, mini-fruticose to mini-foliose cephalodia with a high diversity of Nostoc cyanobionts. The cyanomorphs can apparently exist independently in some cases, although the apothecia on such cephalodia on a specimen from Réunion were unexpectedly found to belong to the chloromorph. The genus and related genera forming the ‘Physma group’ are probably evolutionarily old, and their weak affinity to the remaining part of Pannariaceae, concentrated in the Southern Hemisphere, is discussed. The genus includes 13 known species, and the generitype is Gibbosporina boninensis from the Japanese Ogasawara Islands, originally described as Psoroma boninense and recombined here. The following 12 species are described here as new to science, seven of them with molecular support in an LSU and ITS-based phylogram: Gibbosporina acuminata (Australia, the Philippines), G. amphorella (New Caledonia), G. bifrons (Malaysia, New Caledonia, the Philippines, Solomon Islands), G. didyma (Mauritius, Réunion), G. elixii (Australia), G. leptospora (Australia, Papua New Guinea), G. nitida (Australia, Papua New Guinea, the Philippines), G. mascarena (Mauritius, Réunion, Sri Lanka), G. papillospora (the Philippines), G. phyllidiata (Solomon Islands), G. sphaerospora (Australia, Indonesia, Malaysia, the Philippines, Samoa, and with Psoroma sphinctrinum var. endoxanthellum as a new synonym), and G. thamnophora (Australia and the Philippines). Except for the phyllidiate G. phyllidiata and for G. thamnophora which has cephalodia adapted for vegetative propagation, the species are all primarily fertile. A key for determining the species is provided.

Three lichen species, Hypogymnia physodes, Bryoria capillaris and Peltigera canina were fumigated with 215 μig m−3 of SO2 (6 h per day, 5 days per week) in exposure chambers under three different moisture conditions. The treatments were (1) low humidity (40–50° r.h. continuously), (2) high humidity (80–90° r.h. continuously) and (3) high humidity + water (80–90° r.h. + daily moistening). The value of light microscopy, fluorescence microscopy and electron microscopy in assessing the SO, injury in the lichens was compared. The three lichen species studied were all damaged by this level of SO, fumigation, and injury increased with increased duration of exposure. Electron microscopy was the most sensitive method of revealing cellular injuries after 5 days of exposure in all the species studied. Fluorescence microscopy revealed changes in the colour and intensity of fluorescence after 10 days of exposure in the two epiphytic species, but no clear changes in the cyanobacterial cells of P. canina could be detected by this method. Light microscopy revealed plasmolysis of the algal cells in the two epiphytic species after 10–15 days of fumigation. All the species studied were clearly more sensitive to SO2 when cultured in air of high humidity, although slight cellular injuries also occurred in the dry air treatment (40–50° r.h.). Additional daily moistening tended to protect against injury in the lichens cultured at high humidity. In the present continuous flow fumigation chamber P. canina proved to be sensitive to SO2 in regard to ultrastructural injuries that could be observed in both the cyanobacterial and fungal cells.