Placopsis antarctica, which is apparently endemic to antarctic regions south of lat. 60°S (South Orkney Is, South Shetland Is and the Antarctic Peninsula), is described. Details of its morphology, anatomy, chemistry, ecology and distribution are given. Placopsis bicolor is newly reported from South Georgia. A revised key to species of Placopsis occurring in South Georgia and Antarctica is given.

The responses of the nitrophytic green algal lichen Xanthoria parietina to varying nitrogen (N) concentrations were investigated by collecting 67 X. parietina thalli from clay roof tiles from 13 sites in Portugal with different exposures to N. Concentrations of total N, chlorophyll a (a marker for the photobiont), ergosterol (a marker for the mycobiont), and thallus specific weight (TSW; thallus dry weight in relation to surface area) were quantified for each thallus to see how biont investments were related to thallus N concentrations. Thallus N ranged from 11 to 43 mg g−1 DW revealing a wider N concentration range in this lichen compared to other green algal lichen species. Both chlorophyll a and ergosterol concentrations increased with increasing thallus N, with a steeper increase of the photobiont marker. TSW was similar in all thalli without any significant effect of thallus N concentration, suggesting that thallus developmental patterns are similar in low and high thallus N concentrations. The relatively higher resource allocation to the photobiont in relation to the mycobiont with increasing thallus N concentrations is an indication of the capacity of X. parietina to meet the C demands associated with N assimilation. This result is also in agreement with the inter-specific resource allocation pattern for green algal lichens across the same N concentration range.

Melanohalea nilgirica Divakar & Upreti is described as new to science. Melanelixia glabroides (Essl.) O. Blanco et al., Melanohalea poeltii (Essl.) O. Blanco et al., M. septentrionalis (Lynge) O. Blanco et al., Parmelia isidioclada Vain., P. masonii Essl. & Poelt, Parmelinopsis afrorevoluta (Krog & Swinscow) Elix & Hale and Parmeliopsis ambigua (Wulfen) Nyl., are new records for the Indian lichen flora.

Biogeochemical signatures were compared in ‘living’ and ‘dead’ Parmelia sulcata samples with their oak bark substratum. Eighteen elements reached maximum concentrations in ‘dead’ lichens, at lower concentrations than reported from industrial regions. High N concentrations in ‘dead’ lichens confirm exceedances of critical levels established for deciduous woodlands, supported by alien algae and ‘nitrophytic’ lichen colonization. Negative δ15N values recorded in lichen samples indicate N originated mainly from ammonia. Less negative δ15N values in healthy samples near busy roads suggest local NOx accumulation by Parmelia. Higher δ15N values in bark may result from different processes. Twenty-eight elements reach higher concentrations in healthy lichens near roads carrying higher traffic volumes. Thirteen elements correlate positively with lichen δ15N, suggesting that δ15N is a powerful indicator of the balance between agricultural and vehicular N influx. Maximum Ca and Sr concentrations recorded in bark and their spatial distribution suggest a local geological origin. High concentrations of Ga, Ba, Pb and Ni bark contents testify to a previous pollution legacy, including that from petrol which carried higher lead concentrations than today. Mn concentrations are higher than reported from other studies and show no clear relationship with local roads. Mn is known to limit lichen diversity and health in coniferous forests in US and Germany, but not yet in deciduous woodlands. Current atmospheric conditions and the former pollution legacy must be understood to conserve epiphytes and for biomonitoring.

FT-Raman spectra have been obtained from the highly pigmented lichen Cryptothecia rubrocincta from a Brazilian vestigial rainforest habitat. Spectral signatures of the two main lichen substances, chiodectonic acid and confluentic acid, were identified in adjacent zones of the thallus. Of the characteristic zonal colours displayed by the thallus, the outer red zone contained chiodectonic acid and no calcium oxalate, and graded into by a pink zone with calcium oxalate monohydrate (whewellite) in association with chiodectonic acid, to the inside of which is a concentric white zone containing calcium oxalate dihydrate (weddellite); however, chemically differentiated sites (elliptical brown flecks with a major axis of c. 15 μm) in both the pink and red zones contained chiodectonic acid and calcium oxalate monohydrate. The role of Raman spectroscopy in the spatial identification of lichen substances in the thallial structures is demonstrated.

Two new species of Mycobilimbia are described and compared with other members of the genus: Mycobilimbia australis Kantvilas & Messuti from austral, cool to cold temperate regions, and Mycobilimbia meridionalis Kantvilas from Tasmania. Two additional, superficially similar species that are widespread in the Northern Hemisphere, M. hypnorum (Lib.) Kalb & Hafellner and Bilimbia lobulata (Sommerf.) Hafellner & Coppins, are recorded from Tasmania for the first time.

The development of isidia in thalli of Pseudevernia furfuracea from the Carnic Alps (North-eastern Italy), and the effects of these structures on CO2 gas exchanges were investigated. The ontogenetic events were studied by comparison of sections stained with different histochemical tests and SEM observations. A high cell turnover rate in both symbiotic partners is the first sign of isidium development, followed by an increased aplanosporogenesis of algae and growth of neighbouring medullary hyphae which become oriented upwards. Large nuclei and an intense cytoplasm activity characterize the mycobiont cells. The surface of very young isidia shows an irregular structure of spherical to ovoid protruding tips of perpendicular cortical hyphae, that are later organised in a pseudomeristematic area similar to that observed in the apex of growing lobes. CO2 gas exchange measurements carried out in the laboratory confirmed the high metabolic activity of isidia. At optimal water content and favourable light conditions, isolated isidia had rates of gross photosynthesis and dark respiration that were twice those of non-isidiate lobes. Isolated isidia also had a very low CO2 saturation point, probably because of their favourable surface/volume ratio, and a high light saturation, probably linked to their high content of photosynthetic pigments. The different roles played by isidia in the biology of Pseudevernia furfuracea, and particularly their rejuvenating effect on aged lobes, are discussed, and the presence of thalloconidia is briefly mentioned.

Lecidea kelica Stirt., formerly accepted as a corticolous species of Catillaria is shown to belong to a new, monospecific genus here described as Stirtoniella in the family Ramalinaceae. Details of Stirtoniellia kelica, its synonymy, chemistry, ecology and distribution are presented. It is known from New Zealand and Tasmania.

A corticolous species, Anisomeridium flavovulcanus, is described. It has so far been found in the Carribean and Pacific lowland rainforests of Costa Rica, where it is a frequent lichen in the understorey. This conspicuous lichen is characterized by large conical conidiomata, which release a yellow conidial mass at the apex. Dimorphic conidia occur in the same conidiomata: 1-septate microconidia and thick walled globose macroconidia. Ascomata were found only twice; the inconspicuous perithecia are hemispherical, semi-emergent with an apical ostiole, the asci are cylindrical with a cruciform ocular chamber and the ascospores are uniseriately arranged.

Epiphytic lichens were sampled on selected trees in 19 sites radiating from Chiang Mai city including the adjacent mountain Doi Suthep in Northern Thailand using the VDI method (Verein Deutscher Ingenieure) to obtain frequency of occurrence in 10 area units per sampled tree. Sites selected included highly polluted sites in urban and adjacent industrial areas of Chiang Mai city, disturbed rural sites and undisturbed forest on Doi Suthep mountain, with altitudes varying from 260–1450 m. Lichen diversity was highest in upland sites and lowest in urban and agricultural sites. Analysis of lichen taxa at generic and at macrolichen species level and environmental data using PRIMER showed that upland and lowland sites were distinguished in the first division at both levels and correlated with altitude and vegetation type. Analysis of all taxa at generic level showed no separation of lowland sites but at macrolichen species level a better separation was obtained, suggesting that lichen diversity alone cannot be used for biomonitoring of air pollution. The relationship of epiphytic lichens to climate and pollution data available for Chiang Mai city and Doi Suthep is discussed and results compared with data from other studies in SE Asia.

The localization of inorganic contaminants in lichens is an important step toward a better understanding of the accumulating capability and toxitolerance of species (Hauck et al. 2002). Different methods, such as sequential elution technique (Brown 1995; Tretiach et al. 1999), X-ray microanalysis (Hauck et al. 2002) and microscopic histochemistry (Garty & Theiss 1989), have been used.

Small clay cubes, fired at different temperatures and mounted with nylon touch and close fastener (Velcro®) on acrylic glass plates, were used in an experimental design to study colonization of artificial substrata by lichens. The cubes were exposed in alpine streams for either 5–7 y at five different sites in the Swiss Alps: Flüelatal (three sites) and Brigels (Canton of Graubünden), and Eggerberg (Canton of Valais). Only a few cubes were lost, except at two sites, where complete plates were lost – due to the strong water current and, probably, trampling by cattle. After 3 y, freshwater lichens had grown at three sites. At the most elevated site, colonization was observed after 4 y; at one site no lichen growth was recorded. The first colonizers of the new substrata were the locally most common species. Freshwater lichens preferred the surfaces of clay cubes fired at lower temperature, whereas exposed pieces of local rocks were less frequently colonized. Improvements in the experimental design are suggested.

Schaereria dolodes (Nyl. ex Hasse) Schmull & T. Sprib. comb. nov., an epiphytic lichen species known from western North America was originally described as a member of the genus Lecidea sensu lato. However, its morphology is very characteristic of the genus Schaereria Körb. Here, we lectotypify the species and propose its placement in the latter genus. It is also reported as new to Canada from British Columbia.

The growth of the alpine lichen Cetraria nivalis was followed in a chronosequence of 240 years of primary colonization in a glacier foreland in the Jotunheimen mountain range and National Park in Norway. The largest thallus of C. nivalis was 96 mm in diameter. It was found in the area that had been exposed for a maximum of 240 years. If this individual thallus became established at about the time the habitat was exposed, its average annual diameter increase has been 0·4 mm per year. The growth curve of C. nivalis does however exhibit a pattern of fast growth in the first years followed by a decrease in growth rate. In contrast the population density of C. nivalis increases through time in a linear manner, from 0·4 thalli/m2 in the areas recently exposed to 10·5 thalli/m2 in the sites exposed for maximum of 240 years. This suggests a fairly stable flow of propagules over the landscape through the years. The size distribution (population structure) of thalli within the foreland is skewed, with many small individuals and few big ones.

Our close colleague for 30–40 years, the late Mason E. Hale Jr (1928–1990), was one of the most outstanding lichenologists of the 20th century. While he was terminally ill, he was anxious to complete his world monograph of Xanthoparmelia which he saw through to publication, and accepted 406 species (Hale 1990). Throughout the later periods of his career, his major aim was to document and describe the enormous extent of diversity in the graphidaceous and parmelioid lichens worldwide, and especially in the tropics where he travelled and collected extensively, describing numerous species new to science, 386 in parmelioid groups (Hale & DePriest 1999). In his later years he had, understandably, little time for the nuances of the Code, and, if the principle of adopting proposals for the protection of Names in Current Use (Greuter 1991) had been adopted this would have not caused problems. Sadly it was not, which means that some issues have to be reconsidered. One of these is the correct name for one of the commonest species of Xanthoparmelia, for which he used the name X. somloënsis in his monograph. During the last 15 years, many lichenologists have followed Hale in adopting X. somloënsis, but the nomenclaturally correct name for this species proves to be X. stenophylla.

The effects of two logging strategies and edge effects on cover and abundance of the epiphytic chlorolichens Cavernularia hultenii, Platismatia glauca and P. norvegica were studied in an experimentally logged boreal spruce forest. Whether lichen size distribution within the three species was affected by logging regimes was also tested. One hundred and ten branches were sampled at random within: (1) fine-grained clearcuts consisting of 23 cutblocks 0·25 ha each; (2) coarse-grained clearcuts consisting of 3 clearcuts 2·25 ha each; and (3) a control area.

Of the three species studied, C. hultenii was the most vulnerable to logging, with an abundance much lower in logged areas than in the control area. By contrast, P. glauca was equally abundant in the fine-grained area and in the control area, but significantly less abundant in the coarse-grained area where it seems to have been adversely affected by a pronounced edge effect. No such edge effect, however, was noted in the fine-grained area. Juvenile thalli of C. hultenii and P. glauca were less frequent in the coarse-grained area than in the fine-grained and control areas, suggesting that the juvenile stage might be more sensitive to logging than mature thalli. These results indicate that creation of large clearcuts (2·25 ha) may not be in accordance with the goal of maintaining population size in either C. hultenii or P. glauca. However, P. glauca does not seem to be negatively influenced by a fine-grained logging pattern. No effect of logging strategy or distance from the forest edge was observed on P. norvegica. It follows from the above that any management plans aimed at maintaining population size should be based on an understanding of ecology and life history gleaned from the area in question.

Peltigera didactyla (With.) J. R. Laundon has a cosmopolitan distribution, but in the Antarctic it is very restricted and is nowhere common or abundant, occurring at a number of sites in the northern maritime Antarctic extending to 65°S (Øvstedal & Lewis-Smith, 2001). Within its Antarctic distribution it appears to be most frequent on Signy Island, South Orkney Islands. Typically, this species grows as small colonies amongst mosses in relatively dry, gravelly, sheltered habitats, forming aggregations of lobed sorediate thalli up to c. 10–15 (rarely to c. 25) cm diameter.

The map of the world-distribution of taxa in the genus Leioderma Nyl. (Galloway & Jørgensen 1987: 363, fig. 14), gives the impression that this genus has two species in Peninsular Malaysia, but when checking on the cited specimens there is only one recorded from that region, namely Leioderma sorediatum D. J. Galloway & P. M. Jørg. collected by Gunnar Degelius at Fraser's Hill in Pahang (UPS). However, when going through some herbarium material of the Pannariaceae from TNS, I found well-developed specimens of another species, Leioderma erythrocarpum (Delise ex Nyl.) D. J. Galloway & P. M. Jørg., collected in the Cameron Highlands [alt. 1500–1800 m, 9 viii 1973, K. Suigiyama (TNS)] in Pahang, verifying its presence in the forests of Peninsular Malaysia. This also confirms the special status of these lichenologically poorly known forests (see e.g. van Steenis 1962 on the montane forests of the Malaysian region), where amongst other things some of the most typical SE Asian species of Erioderma also occur, viz. E. phaeorhizum Vain. and E. tomentosum Hue (as well as E. sorediatum P. M. Jørg. & D. J. Galloway, see Jørgensen & Sipman 2002). The nearest previous records of L. erythrocarpum are from montane forests in Borneo and Java (Galloway & Jørgensen 1987: 383).