The phylogenetic relationship between the Alectoriaceae and the Parmeliaceae (lichenized ascomycetes) were studied using sequences of the small subunit of the nuclear ribosomal DNA (SSU rDNA). The Alectoriaceae was represented by specimens of Alectoria ochroleuca and A. sarmentosa, and the Parmeliaceae by Bryoria capillaris, Cetraria islandica, Cornicularia normoerica, Evernia prunastri, Hypogymnia physodes, Parmelia saxatilis, Platismatia glauca, Pleurosticta acetabulum, Usnea florida, Vulpicida juniperina, V. pinastri and Xanthoparmelia conspersa. The results suggest that the Alectoriaceae is derived from within the Parmeliaceae, and it is suggested the families should be treated as synonyms. Morphological and anatomical characters are discussed, and it is concluded that earlier investigations might have overemphasized minor variations in ascus structure.

Sulcopyrenida H. Harada gen. nov. is described. It differs from other genera of Pyrenulaceae by having longitudinally sulcate spores. The genus is represented by two species: S. canellae-albae (Fée) H. Harada comb. nov. and S. staurospora (Tuck.) H. Harada comb. nov. Both species have been previously reported from N. and S. America, and the latter species is now reported from Asia.

Three species of Porina (Trichotheliaceae), P.kansriae P. M. McCarthy, P. siamensis P. M. McCarthy and P. wolseleyae P. M. McCarthy, are described from aquatic and semi-aquatic rocks in montane rainforest in north-eastern Thailand.

Two new species of Psoroma with unusual cephalodia are described: P. echinaceum with isidiate cephalodia, from southern South America and P. geminatum with fragile phyllidiate cephalodia, from New Zealand and Australia. These are additional to two previously described species producing dispersal units on their cephalodia, P. durietzii P.James & Henssen (with soredia) and P. aphthosum, Vain. (syn. nov. P. dimorphum Malme) (with isidia). This is a strategy development that ensures successful establishment of new thalli.

Lichenopeltella coppinsii Earland-Bennett & D. Hawksw. is described as a new species growing on Verrucaria muralis in Norfolk. It is compared with other species of the genus occurring on pyrenocarpous lichens in particular, and is close to the species informally called ‘L. hydrophila R. Sant.’, a name that has never been validly published.

The new species Peltigera phyllidiosa Goffinet & Miadlikowska from the Southern Appalachians, eastern U.S.A., is closely related to P. collina and P. neckeri. Like these species it has a glabrous upper cortex and black fingernail- or saddleshaped apothecial discs, but differs in its laminal phyllidia. Variation in nucleotide sequences of the Internal Transcribed Spacer (ITS) of the nrDNA repeat region correlates with the presence or absence of phyllidia, supporting the distinction of P. phyllidiosa from P. collina and P. neckeri.

Thallus organization is examined in Aspicilia californica Rosentreter, fruticose lichen known from several localities in central and southern California. The sprawling, terete thallus branches possess a dense central medulla of thickwalled, longitudinally oriented fungal cells. This central tissue emerges at branch apices to form a darkly pigmented fungal tip. Thallus development involves the apical extension of the tip to produce a fungal tissue over which a cylindrical algal layer and cortex will eventually be formed. Apical branches are initiated by furcation entirely within the fungal tip. Lateral branches, emerging from the lichenized thallus, arise as a divergent bundle of elongate fungal cells originating in the medulla. The photobiont appears to play no direct role in initiation of apical or lateral branches. It is concluded that thallus development in A. californica occurs with a relatively low degree of synchrony between mycobiont and photobiont growth, similar to the pattern observed in crustose lichens with prothallic growth. A rather similar type of thallus organization is observed in A. hispida, although in that species mycobiont growth and branch initiation appear to be somewhat more closely associated with algal cell proliferation. A squamulose Aspicilia from central Spain produces rhizomorphs that may sometimes become invested with an algal layer and cortex, resembling the thallus axes of A. californica.

Porina pseudoapplanata Lücking & Cáceres sp.nov. is characterized by its foliicolous growth habit, a thin, nitidous thallus without crystals, applanate, yellowish red perithecia narrowly bacillar, 7-septate ascospores, and the presence of previously unrecognized isidi belonging to the Phyllophiale-type, here formally described as P. viridis Lücking & Cáceres sp.nov. The interpretation of Phyllophiale representing isidia of Porina species is discussed. Porina pseudoapplanata is similar to species in the P. rufula group, i.e. P. monocarpa (Kremp.) F. Schill., P. cupreola (Müll. Arg.) F. Schill., P. planiuscula Vêzda and, in particular, P. applanata Vain. However, it seems most closely related to P. mirabilis Lücking & Vězda in the P. epiphylla group, from which it differs by the complete absence of crystals in the thallus and perithecia. This gives a further insight into systematic relationships within the Trichotheliaceae. Keys are presented to distinguish P. pseudoapplanata from similar and related species, as well as to the known species of Phyllophiale.

Epiphytic lichens were recorded on wayside trees in the Netherlands. Four statistical methods were used to detect the relationship between presence and abundance of lichen species and measured atmospheric concentrations of SO2, NO2 and NH3. The observed relationships were compared to published indicator scales of lichen sensitivity to atmospheric pollution. For SO2, a good agreement was found between all scales and calculated sensitivities based on presence or absence of species. For NO2 and NH3 the correspondence was less obvious. The sensitivity to NH3 was inversely related to Wirth's;s acidity indicator positively to NH3 tend to be sensitive to SO2 and NO2.

Phylogenetic trees based on group I intron sequences and on internal transcribed spacer (ITS) sequences of mycobiont ribosomal genes were calculated and compared. Eight cetrarioid and four non-cetrarioid species of the Parmeliaceae were compared. The phylogeny based on group I intron sequences is partly congruent with the ITS sequence phylogeny. Group I intron sequences are presumably less informative for infragenic studies. The introns have a length of 214–233 nucleotides, and differ at up to 33% of the bases between species. All introns analysed are located between the positions 1516 and 1517 of the fungal 18S ribosomal RNA gene. Cetrarioid lichens form a non-homogeneous group within the Parmeliaceae according to both group I intron and ITS sequences.

Morphological and chemical data from 64 genera of Parmeliaceae, including the most common genera in Europe, were analysed by means of neighbour–joining and parsimony analysis. Two presence/absence matrices were constructed, one for the 64 genera and a smaller one for the most common European genera. Probabilities were too low to allow grouping of the genera and only a few pairs of genera had a probability of >50% for both matrices. A molecular matrix (nuclear rDNA-ITS) of the most common genera in Europe was constructed and analysed by the method of maximum likelihood. These results were much more informative than the non-molecular matrix for establishing phylogenetic relationships among the genera.

This paper provides a revision of the foliicolous representatives of the Gyalectaceae in Costa Rica. Five species of Coenogonium and 13 of Dimerella are distinguished. Coenogonium interplexum, C. interpositum, C. leprieurii, C. linkii and Dimerella vezdana are ubiquitous as to the choice of their substratum, whereas C. moniliforme and Dimerella lutea are facultatively foliicolous. The remainder are typically foliicolous taxa but may occasionally be found on bark. The following species are for the first time reported as foliicolous from Costa Rica: Coenogonium interplexum, C. interpositum, C. leprieurii, C. moniliforme, Dimerella fallaciosa, D lisowskii, and D. aff. pilifera. Three new species are described: Dimerella isidiifera sp. nov. with disciform isidia, D. subzonatasp. nov. with small, bright yellow, dentate apothecia and a whitish prothallus, and D. siquirrensis sp. nov. with large, orange apothecia and a thin whitish prothallus. A key is presented for neotropical foliicolous Gyalectaceae, and notes on the distribution and ecology of the species are given.

Psammina inflate Earland-Bennett & D. Hawksw. and P. simplex Earland-Bennett & D. Hawksw. are described as new species from coccoid green algae and crustose or leprose lichens in lowland Britain. Additional records and hosts for P. stipitata are reported, and a key to the four species now known in the British Isles is presented. Psammina simplex is the more strongly pathogenic of the species, eventually destroying its hosts. The discovery of these new sp cies adds weight to the view that the genus is more appropriately regarded as a hyphomycete rather than an acervular coelomycete. The size, shape and septation dimensions of the conidial arms were found to be the most reliable characters for specie separations in the genus. Pycnopsammina lobariae Diederich & Etayo is also cited from the British Isles for the first time.

A survey of epiphytic species on annual increments of Quercus petraea twigs in a west Wales woodland has shown that distribution of lichen species and rates of succession are affected by a range of environmental conditions. Lichen communities were recorded for 1–15 years on randomly sampled twigs along marked woodland boundaries affected by a range of climatic and management conditions. Results show that there is a correlation between environmental condition and lichen communities of twigs, and that indicator species can be used to detect trends towards acidification or eutrophication.

A survey aimed at studying the effects of hydrogen sulphide (H2S) on epiphytic lichen vegetation was carried out at Acquapassante (Mt. Amiata, Central Italy). In 1992, lichen vegetation was surveyed using a sampling grid often units, on 18 chestnut trees along a transect from a chimney emitting H2S to c. 200 m in the direction of the prevailing winds. A Lichen Biodiversity Index (LBI) was calculated as the sum of the frequencies of all species present within the grid. The same survey was repeated five years later. Concentration Analysis was applied to describe the data structure, and Procrustes Analysis was used to verify the congruence between the ordinations of 1992 and 1997. The statistically significant linear and non-linear regressions found between environmental variables (distance of relevés from the chimney, bark pH, lichen biomass of selected foliose and fruticose species, total sulphur content of Evernia prunastri, Hypogymnia physodes, Parmelia sulcata and Ramalina fastigiata) and the position of the relevé points on the ordination axes suggest that species distribution along the transect is related to differences in H2S tolerance. However, some crustose species (Lecanora cf. conizaeoides, L. saligna and Scolkiosporum umbrinum) should be probably excluded from the computation of the LBI for monitoring purposes, as their optimum is in the immediate vicinity of the H2S source.

A protocol is described to enable the production of reliable genetic fingerprints of lichen-forming fungi using randomly amplified polymorphic DNA (RAPD) markers. Key features of the method are the use of mycobiont DNA extracted from axenic cultures by a phenol-chloroform procedure, and PCR amplification using DyNAzyme II DNA polymerase. RAPD-PCR fingerprints of Graphis scripta, G. elegans and Phacographis dendritica were successfully generated using this protocol and individual isolates could be identified on the basis of differences in banding patterns produced. DNA extracted from whole thalli of G. scripia was also subjected to RAPD-PCR but the fingerprints produced differed from those given by axenic cultures of the mycobiont. Therefore difficulties of interpretation may arise when whole thalli are used in RAPD analysis.

The results from several floristic and bioindication projects in Central Switzerland (1986–1998), focusing on the effects of agriculture, particularly from nitrogen and agrochemical emissions, are summarized. The abundance of nutrienttolerant lichen species and the decreased occurrence of nitrophytic lichens are both correlated with agricultural land use and high atmospheric deposition. The impact could be demonstrated not only by the distribution patterns of nutrient-tolerant species, but also by the high N content of lichens such as Physcia caesia. Positive growth response of Cetraria islandica to application of mineral nutrients and increased CO2 in open-top chambers at high altitudes was also observed. The methods and a survey of the results from studies conducted within the framework of the lichen research programme of the Natural History Museum of Lucerne are presented here. A discussion of the issues shows the need for further studies concerning the influence of introduced nutrients on the biodiversity of lichens.

The genus Fenestroconidia is described to accommodate the new species Fenestroconidia caloplacae. This lichenicolous fungus produces black sporodochia, has comdiogenous cells arranged in chains, and simple, pale brown conidia with a subhyaline guttule-like zone. It is known only from central Spain (Cuenca province), growing in the apothecia of Caloplaca saxicola s.lat.

Using a sequential elution procedure, the cellular location of Cl−, Na+, Mg2+, K+ and Ca2+ was determined in the lichen Ramalina canariensis from the southwest coast of Portugal. After a dry deposition period, a logarithmic decrease in the extracellular (surface and wall-bound) concentration of Cl−, Na+ and Mg2+ was observed with increasing distance from the coast. The importance of each cellular fraction as an indication of the airborne salts was identified using factorial analysis methods, as was the relationship between the extracellular and intracellular concentration of the saline elements. The factorial analysis showed that the most important elements for the biomonitoring of airborne salinity were Cl−, Na+ and Mg2+. However, for the cations, only the surface and wall-bound (for Na+) fractions seem to be related to sea-salt deposition on the lichens. The intracellular fractions of these elements are relatively independent of the surface and wall-bound concentrations, or reflect some non-linear processes induced by extreme extracellular concentrations. Although they may represent a significant proportion of the total element concentration, intracellular element concentrations are of little value in monitoring salt deposition, due to physiological control by the organism. The use of total analyses, without any fractional differentiation, can be a biased method for biomonitoring the accumulation of salt spray by lichens, because it includes the intracellular fraction, which may be independent of the deposition taking place. The use of the different cellular fractions provides a more informative indication of the deposition of atmospheric elements, while also giving information on any physiological alterations induced by the specific environmental chemical factors, including membrane damage.

A community ecology approach using an association of species test and a principal component analysis resulted in the recognition of two major and two minor foliicolous lichen communities in a neotropical rainforest. The major communities arc governed by microclimatic factors, one characteristic of the shady understorcy and the other confined to light gaps. The minor communities are due to subtle phorophyte preferences towards palm and dicot leaves. The shady understorey community is dominated by the families Anhoniaceae, Opegraphaceae, Tnchoihdiaceae and Pilocarpaceae, which predominantly have Phycepeltis as their phycobiont, thin thalli, abundant sexual reproduction, small ascospores produced in high numbers, and pyenidial conidiomata. The light-gap community is mainly composed of the families Gomphillaceae and Ectolechiaceae, with Trebouxia as their phycobiont, thickly crystalline or whitish, dispersed thalli, frequent asexual reproduction, large ascospores produced in low numbers, and specialized campylidia and hyphophores as conidiomata. Phycobiont, thallus structure, and the mode of reproduction are considered as adaptations to different microsites, whereas the shape and size of ascospores and conidia seem to be of less importance. The foliicolous lichen communities reflect the spatial and temporal structure of the forest, in particular the continuity of the shady understorey in comparison to the discontinuity of the light gaps. While the formation of the shady understorey community follows more deterministic patterns, the light-gap community exhibits high stochasticity.