Current knowledge about the non-lichenized genus Chaenothecopsis in Switzerland is reviewed. A characterization of the genus and a key to all accepted European taxa are presented, excluding the little known resinicolous species. The distribution of the 15 Chaenothecopsis species recorded in Switzerland is briefly summarized. Specimens in the herbaria belong mainly to C. pusilla, C. rubescens and C. viridialba; recent collections include rarer species such as C. hospitans, C. ochroleuca, C. retinens and C. tasmanica. It seems that many taxa occur predominantly in montane to subalpine forests in the Northern Prealps, although distributional data are still scarce.

Bacidia pycnidiata sp. nov. (Ramalinaceae) is described from Poland and the Czech Republic. It is the first species within Bacidia s. lat., referable to the Bacidina group, known to have sessile, long-necked, lageniform pycnidia bearing straight macroconidia. It has been found growing on saxicolous as well as on corticolous bryophytes and directly on bark of deciduous trees within young, hardly changed woodlands or in the vicinity of human settlements.

Two new Pertusaria species with brown ascospores are described from southern California and Baja California, Mexico. Pertusaria islandica sp. nov. is characterized by pertusariate to pseudolecanorate ascomata, ellipsoid ascospores, 8-spored asci, a strongly K+ violet reacting epithecium, and the presence of the 2′-O-methylperlatolic acid chemosyndrome, while P. occidentalis sp. nov. has pertusariate ascomata, globose to subglobose ascospores, 8-spored asci, and contains the arthothelin chemosyndrome. Pertusaria ochracea Kremp. is reduced to synonymy with P. melanospora Nyl.

Porina pilifera Neuwirth sp. nov. is described from Costa Rica. It is similar to P. palmicola, but differs in having smaller ascospores 27–36×3–4 μm. Porina pilifera is only known from the type locality in tropical Central America, where it grows on the leaves of palm trees.

The new species, Lecanora luteomarginata and L. subpraesistens, are described from northern India. The first is characterized by apothecia with dark brown discs and bright yellow margins, while L. subpraesistens is a multispored species that is readily distinguished by an egranulose epihymenium and a melacarpella-type amphithecium.

In order to ascertain the extent of possible host-specialization in the Nesolechia oxyspora complex, as a pilot study ascospores from 20 collections from different parmelioid hosts representing seven genera were drawn, measured, and had length:breadth ratios calculated. The data were then subjected to multiple regression analysis using Huber-White sandwich estimators of standard errors (apparently not previously used in mycology) which take account of spores not necessarily being independent variables as they might come from the same ascus, and a statistical analysis. Significant differences between collections from seven genera were found. While the sample size was too small to reach definite conclusions, it is clear that there is a finer degree of host-relatedness than hitherto expected, which may be geno- or phenotypic. A more extensive study including species from a wider range of hosts and complemented by molecular methods will be necessary to further elucidate degrees of specificity and cryptic co-speciation in the complex. A list of the 63 reported lichen hosts is included; these are distributed though 19 genera.

Primers are presented to amplify an intron-containing portion of the actin type I locus from Asterochloris algae. The amount of variation and phylogenetic resolution provided by the ITS rDNA are compared with that from the actin locus. The number of variable and parsimony-informative sites within the actin locus was drastically higher than that of the ITS. Phylogenetic analyses of the ITS resulted in poorly resolved trees with low support values. In contrast, phylogenetic analyses of the actin locus yielded trees with better support and resolution. It is concluded that the actin type I introns will be useful for studies investigating species concepts and population genetics.

Nephroma occultum is a COSEWIC listed cyanolichen of “Special Concern”. It is endemic to old-growth cedar-hemlock forests in western North America. This is the first study to place N. occultum into a phylogenetic framework using nucleotide sequence and secondary structure data. It also addresses the phylogenetic relationship between N. occultum and N. arcticum. Analysis of fungal Internal Transcribed Spacer (ITS) ribosomal DNA (rDNA) produced four major clades. The cyanobacterial transfer RNALeu intron (tRNALeu) from N. occultum was separated from that of N. isidiosum and fell between the Eurasian and North American epiphytic taxa. Examination of length and complexity of the folded secondary structures revealed different trends in the ITS1 and ITS2 rRNA regions. Even though N. occultum is endemic to North America, it seems more closely related to South American temperate rainforest species than to the sympatric N. arcticum. Nephroma occultum is alone among the studied species of Peltigerales in having an exceptionally long ITS1 region, and a different tRNALeu intron DNA sequence of the photobiont suggesting association with a unique genotype of Nostoc. It may be argued that the fitness of N. occultum may be influenced by the complex ITS1 RNA structure, a unique photobiont genotype undergoing a genetic bottleneck, no sexual reproduction to generate variation, and the inability to associate with different photobionts to adapt to changing habitats.

Healthy thalli of Parmelia sulcata Taylor were transplanted to 8 localities in the surroundings of a power station (La Robla, León, Spain), the sole pollution source in the region. Changes in chlorophyll a fluorescence were monitored in the transplants 12 months, 18 months and 24 months after transplantation. Statistically significant differences were observed in the ratio of variable to maximal fluorescence, non-photochemical fluorescence quenching and vitality index. The decrease in fluorescence parameters was higher in the localities of Cuadros and Rabanal de Fenar, which are situated a few kilometres away from the power station and in the same direction as the prevailing winds.

The genetic diversity of photobionts in the lichen Protoparmeliopsis muralis was examined to determine the identity of the photobiont and the level of selectivity for the photobiont by the mycobiont. Forty ITS rDNA sequences of photobionts from thirty nine specimens of Protoparmeliopsis muralis have been determined. The photobiont species were identified both by direct comparison with the available sequences and by phylogenetic analysis. The sequences obtained from P. muralis specimens belonged to different Trebouxia clades. The most common photobionts were T. incrustata and an unidentified lineage, here named as “muralis I”. Less common photobionts were T. asymmetrica and T. gigantea. Two unidentified Trebouxia spp. and a photobiont that belonged to the clade that includes T. impressa, T. flava and T. potteri were also found to be associated with P. muralis. Such flexibility has not been reported to date. Moreover, two different photobionts were found in a single specimen. They belonged to the T. gigantea clade and “muralis I” lineage. The low level of selectivity with respect to the photobiont may constitute an important aspect in that Protoparmeliopsis muralis is one of the most successful urban lichens in the world.

Induction of secondary compounds in three reindeer lichens (Cladonia arbuscula, C. rangiferina and C. stellaris) was studied under controlled conditions in a growth chamber. Acetone rinsed (secondary compounds removed) lichen mats were subjected to three light regimes (PAR, PAR+UV-A and PAR+UV-A+UV-B), each combined with simulated herbivory (clipping). After 4 weeks, lichen extracts were analyzed by HPLC for any synthesized secondary compounds. UV-B induced the synthesis of usnic acid in C. arbuscula and C. stellaris and melanic pigments in C. rangiferina. Atranorin, fumarprotocetraric acid and perlatolic acid were not influenced by light quality. None of the identified compounds were significantly influenced by clipping. In conclusion, all three lichen species responded to UV-B radiation by developing cortical UV-B absorbing pigments that might function as protective screens. However, the experiment did not produce evidence for a herbivore-deterrent role of compounds studied.

During fieldwork in Siberia and Alaska the senior author has sporadically found an unusual Pertusaria species that was tentatively identified as P. christae Dibben & Poelt. This species has been described from a few localities in the Austrian Alps (Dibben & Poelt 1987) and was recently recorded from the Putorana Plateau in Russia (Zhurbenko 1996). Examination of various herbarium collections confirmed that the species is more widely distributed in the Holarctic, but probably overlooked. Further, its distinction from P. saximontana was unclear. According to the literature, P. saximontana is a corticolous or lignicolous species occurring in North America and containing 2-O-methylconfluentic acid (Dibben 1980; Lumbsch et al. 1999; Wetmore 1967). In contrast, P. christae is regarded as a muscicolous or terricolous Eurasian species containing 2′-O-methylperlatolic acid (Dibben & Poelt 1987). In micromorphological features the two species are very similar, and habitat and chemistry were the main characteristics used to separate the two taxa. In our studies, however, we found 2′-O-methylperlatolic acid in several lignicolous collections from North America, raising the question whether the two species are distinct. Hence, we have studied additional material, including the types of both species to clarify the status of the two described taxa.

Lichen growth and regeneration depend on the net photosynthetic production, the lateral allocation of products, on abiotic factors, competition and herbivory, and may therefore vary both in space and time (Hill 1981). Herbivores cause different damage to lichens in response to different thallus structure (surface toughness) and growth form, presence/absence of secondary compounds, and due to herbivore-specific differences in feeding (Lawrey 1984; Fröberg et al. 1993; Baur et al. 1994; Hesbacher et al. 1995). Regeneration of artificially damaged lichen tissue has been investigated in detail, for example in Xanthoria parietina (L.) Th. Fr. (Honegger 1996; Honegger et al. 1996). However, quantitative assessments of the regenerative capacity of thalli damaged by herbivores are so far lacking. Damage to lichens by grazing gastropods is made by highly specialized radulae and can therefore not be imitated by any mechanical treatment (Baur et al. 2000). Herbivory by snails also involves the production of saliva and mucus, which both could affect lichen regeneration.