The Caloplaca citrina group in the Nordic countries, except Iceland, is analysed with regard to morphology, anatomy, ecology, and chemistry. Their genetic relationship is also analysed using the ITS ribosomal DNA gene. The results show that there are at least five species within what has been called C. citrina, of which four are closely related to one another and to several non-sorediate species. Three of these, C. citrina, C. flavocitrina and C. arcis have previously been recognized at specific or varietal level some time during the last two centuries, whereas the fourth species, C. dichroa, is described as new. The fifth species, C. phlogina, is not related to the other species but shows a close relationship to the Xanthoria candelaria group. The species are described and illustrated in colour. Distribution maps are given for the study area and a key to sorediate, yellow to orange species occurring in the Nordic countries, except Iceland, is also provided.

Arthopyrenia tuscanensis Coppins & S. Ravera and A. coppinsii S. Ravera are described as new to science. They share the characteristic tadpole-shaped ascospores with a conical lower cell, but are otherwise comparable to A. salicis A. Massal.

Bactrospora perspiralis, B. subdryina, Enterographa mesomela, Graphidastra laii and Lecanographa atropunctata (Roccellaceae) are described as new to science based on specimens collected in the wet subtropical lowlands of northern Thailand and Vietnam. The new Graphidastra is the third species in the genus and was also found in Taiwan.

Topeliopsis darlingtonii A. Frisch & Kalb and Topeliopsis elixii A. Frisch & Kalb from Australia and Topeliopsis meridensis Kalb & A. Frisch from Venezuela are described as new species. Thelotrema decorticans Müll. Arg. and Ocellularia subdenticulata Zahlbr. are transferred to Topeliopsis and are the correct names for T. corticola Kalb and T. vezdae Kalb, respectively. A revised key of the genus Topeliopsis is presented. Ascoconidia, produced in old ascospores of T. elixii, are described for the first time for the Thelotremataceae.

A first assessment of paralogy in non-reducing polyketide synthases of Parmeliaceae is presented. Primers which are specific to the keto-acyl synthase domain were used to amplify gene fragments of putative non-reducing polyketide synthases from various representatives of the family. The corresponding sequences were analysed together with a selection of known polyketide synthase genes from other fungi, including lichenized fungi. The results suggest that genes from Parmeliaceae represent at least 6 paralogs. Their different positions in the tree partly correlate with the variable presence of spliceosomal introns at particular positions in the gene fragments. Because only one paralog could be unambiguously detected in each species by direct sequencing of PCR products with this approach, we tested the applicability of clade-specific primers, designed by using orthologous signature sequences. With these primers more paralogs could be detected from the same DNA extract in a number of species, but certain paralogs were consistently not amplified in these species. The paralog-specific primer approach can potentially be used for a rapid screening of PKS genes from a broader range of lichen fungi.

The foliicolous lichens and the environmental factors at 14 stations in Catalonia were examined and the relationships between their foliicolous flora and climatic features analysed. This information could be used to predict potential sites with foliicolous lichens in areas with a Mediterranean climate. In addition, two species new to the European lichen flora (Bacidina canariensis and Fellhanera semecarpi) are recorded, and also 8 species new to the lichen and lichenicolous flora of the Iberian Peninsula (Arthonia leptosperma, Byssoloma diederichii, Chionosphaera apobasidialis, Cladosporium arthoniae, Fellhanera christiansenii, Fellhanera seroexspectata, Strigula smaragdula and Vezdaea dawsoniae).

Xanthoria mawsonii C. W. Dodge was found to perform well physiologically in a variety of habitats at high latitudes in continental Antarctica. The net photosynthetic rate of 7·5 μ mol CO2 kg−1 s−1 is exceptionally high for Antarctic lichens. Field and laboratory measurements proved the photosynthetic apparatus to be highly adapted to strong irradiance. The cold resistance of the photosystem II reaction centres is higher than the photosynthetic CO2 fixation process. Optimum temperature for net photosynthesis was c. 10°C. The lichen grows along water channels where it is frequently inundated and hydrated to maximum water content, although net photosynthesis is strongly depressed by super saturation. In these habitats the lichen is photosynthetically active for long periods of time. Xanthoria mawsonii also grows at sites where it depends entirely on the early spring snow melt and occasional snow fall for moisture. It has an exceptionally short reactivation phase and is able to utilize snow immediately. Recovery of activity by absorbing water vapour from air, though practically possible, seems to be of ecological importance only under snow at subzero temperatures.

A collection of lichens made in 1998 (by WQ) from the bark of Austrocedrus chilensis at a locality in southern Chile, disclosed two species of Pannaria not hitherto recorded from the Chilean lichen mycobiota (Galloway & Quilhot 1999): (1) the pantemperate taxon Pannaria conoplea (Ach.) Bory, which is widespread in the Northern Hemisphere as well as having rare outliers in East Africa, Venezuela, Ecuador and Australia (see Jørgensen 1978; Swinscow & Krog 1988; Jørgensen & Galloway 1992; Jørgensen & Arvidsson 2004), and (2) Pannaria tavaresii P. M. Jørg., known earlier from North America (including Mexico and Jamaica), Portugal, Macaronesia (Jørgensen 1978), Australia (Jørgensen & Galloway 1992), Sardinia and Italy (Nimis 1993) and previously collected in 1986 from near Valdivia in Chile. The discovery of Pannaria conoplea and P. tavaresii in Chile adds to the known Pannaria mycobiota of Chile (Galloway & Quilhot 1999), bringing the total number of species of this genus in Chile to 23. Eleven taxa formerly placed in Psoroma, are now correctly accommodated in Pannaria (see Jørgensen 2001b; Elvebakk & Galloway 2003; Jørgensen & Sipman 2004; Passo et al. 2004). Both Pannaria conoplea and P. tavaresii are within the currently accepted circumscription of Pannaria (Jørgensen 1994, 2004a, 2004b). Descriptions of the Chilean material are given below.

Sticta wiegelii (Ach.) Vain., a cyanobacterial lichen characterized by mainly marginal isidia, occurs in montane rainforest in both tropical and cool-temperate forest biomes, being known from East Africa (Stizenberger 1895; Swinscow & Krog 1988; Krog 2000), Réunion and Madagascar (Nylander 1868; Hue 1890, 1901a), India (Joshi & Awasthi 1982); Japan (Yoshimura 1974; Kurokawa 2003; Takahashi et al. 2004), Central America and the West Indies (Nylander 1865; Hue 1890, 1901a; Imshaug 1956, 1957; Harris 1984; McDonald et al. 2003), Colombia, Venezuela, Brazil (Martius 1833; Vainio 1890; Hue 1901a; Malme 1934; McDonald et al. 2003), Argentina, Chile (Galloway 1994a), Java (Nylander 1868; Stizenberger 1895; Hue 1901b; Zahlbruckner & Mattick 1956); New Guinea (Szatala 1956; Streimann 1986), north-eastern Australia (Galloway 1998, 2001; McDonald et al. 2003), and several Pacific island groups including Hawaii, Fiji, the Galapagos, Tahiti, New Caledonia and the Kermadecs (for references see Elix & McCarthy 1998: 269; McDonald et al. 2003).