Thelidium pluvium sp. nov. is newly described from rocks in streams in Great Britain, Ireland and Norway. It is characterized by perithecia which are partly covered by a thalline layer, a thin involucrellum, and 1-septate spores. A provisional key is given to species of Thelidium in north-west Europe.

A new species of Lecanora with a yellowish green thallus, Lecanora strobilinoides Giralt & Gomez-Bolea sp.nov. is described. It was found only in SE Catalonia (NE Spain) at low and middle altitudes, growing on bark and lignum of trees and shrubs, mainly on Pinus halepensis and Quercus ilex. Closely related to Lecanora strobilina (Sprengel) Kieffer, it is easily separated by its asci, with (12–)16(–32) ascospores, that are smaller and frequently 1-septate.

Two hundred and three specimens belonging to the genus Cetrelia from the Soviet Union and also 41 samples from other countries have been analysed by TLC. Eight species were determined in the Soviet Union. In addition two new species, C. orientalis and C. pseudocollata sp. nov. are described. Five morphotypes and six chemotypes have been recognized in the genus: their main characteristics are tabulated in a form that can be used for identification and a key is also included. Evolutionary relationships between the ‘primary’ and ‘secondary’ species related to ‘species-pairs’ are discussed.

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.

Two national monitoring surveys were carried out within 5 years, using Parmelia sulcata as a biomonitor of trace-element air pollution. The method of sampling was standardized. The lichen samples were analysed by neutron activation analysis. Local variations in element concentrations in lichens from various deciduous tree species from several sampling sites were established. The geographical concentration patterns obtained from the lichen data sets agreed with the element concentration gradients obtained from one dispersion model and measured data of atmospheric concentrations and deposition. Comparison of the two lichen data sets showed the relationship of the geographical concentration patterns with time. Combination of the available data gave insight into the possibility of localization of pollution sources.

Generalized linear modelling was applied in analysing the bioindicator value of epiphytic lichens for air pollution around an industrial centre in the Siberian mountains using data published previously by Zobel (1988a). The occurrence of taxa on tree boles was systematically related to the distance from the pollution source and to the altitude from sea level. Binomial distribution was postulated to describe the random variation and maximum likelihood and quasi-likelihood methods were used. Zobel had pooled the original data by grouping distance and altitude into three qualitative levels. The model for pooled data with qualitative factors generally had a poor fit. We assigned quantitative values, linear and quadratic contrasts, to the altitude and distance levels and a linear by linear interaction term between altitude and distance. In most taxa the interaction appeared significant, and these models had generally a better fit and smaller overdispersion than qualitative models. Finally, more effective analysis was performed on the original plotwise data utilizing unpublished quantitative information for distance and altitude. Most species (16/19) had a significant and usually positively monotone response to distance. In the majority of these (10/16) the effect of distance varied between the altitude levels most often so that the lichens were scarcer at low altitude and their increase was faster at high altitude.

A recent survey of epiphytic lichens in the Jardin du Luxembourg has shown there to be a marked improvement in the air quality of Paris over the past decade. Recolonization by at least 11 lichen species has occurred during that period. It has taken almost 100 years for epiphytic lichens to re-establish in the Jardin du Luxembourg, where William Nylander in the 1890s was able to amply confirm his far reaching hypothesis, made 30 years earlier, on the direct relationship between lichen survival and air pollution.

Mannitol-1-phosphate dehydrogenase [EC 1.1.1.17] activity was demonstrated in extracts of Pseudevernia furfuracea and Hypogymnia physodes. The reaction was found to be highly substrate specific for fructose-6-phosphate/NADH or mannitol-1-phosphate/NAD+. The pH optimum for fructose-6-phosphate reduction was 7.1, and apparent Km values were 1.2 mM for fructose-6-phosphate and 20 μM for NADH. The reaction did not require Mg++ or Ca++. For conversion of mannitol-1-phosphate into mannitol, the occurrence of mannitol-1-phosphatase in Pseudevernia furfuracea is postulated.