The citrine–green Candelariella flavovirella (Nyl.) Lettau and C. heidelbergensis (Nyl.) Poelt are shown to differ from the yellow-orange species C. vitellina (Hoffm.) Mull. Arg. and C. aurella (Hoffm.) Zahlbr. respectively, mainly in the suppression of calycin. As distinctive and geographically scattered chemotypes it is suggested that the rank of form is most appropriate and the required new combinations are made. A citrine–green population of C. medians (Nyl.) A. L. Sm. is described as f. steepholmensis O. Gilbert f.nov.

Very little is known about how growth is distributed within thalli of fruticose lichens. To determine whether mature, non-apical regions of the beard lichen Ramalina usnea elongate, segments of the broadest axes were marked with thread and measured; thalli were then returned to the field to resume growth for about one year. Growth was evident in all segments measured and increments were roughly proportional to length, suggesting that elongation occurs throughout the thallus. New thallus axes (branches) were organized from buds that emerged from mature tissue, usually along pseudocyphellae and surfaces exposed by breakage. Axes were very fine at their extremities and possessed an inrolled apex from the time of bud emergence. No evidence of apical branching was observed. The thallus cortex consisted of very thick-walled fungal cells oriented longitudinally. In transverse section, cells gave the appearance of being grouped within fascicles, indicating that branch cells grow within the older cell wall material of their neighbours, as occurs in the cortex of Ramalina menziesii and the medullary cord of Usnea longissima. A continued accumulation of cell wall layers may be related to the mature tissue's capacity to sustain elongation growth.

The diminutive species Micarea capitata is described from north-western Sweden. It has been found at two localities in boreal forests where it grew on the bryophyte Hylocomium splendens. Micarea capitata is distinguished by small (0·10–0·35 mm diam.) black apothecia, (0–)1-septate ascospores and a mottled, darkly pigmented hypothecium.

The distribution of different ecological groups of lichens (acidophytes, ‘nitrophytes’, indifferent species) was compared on 1–24 year-old twigs of Abies sibirica sampled in the ‘pristine’ West Sayan and the polluted East Sayan Mountains (Krasnoyarsk District, South Siberia, Russia) to test their value as indicators of current pollution effects. Bark pH of twigs and bark chemistry (N, S, Ca, Mg, Al, Fe) were measured, and a preliminary estimate of emissions in the Krasnoyarsk District from livestock animal populations was calculated. In both regions, an unusually high twig bark pH and an abnormal species composition for A. sibirica canopy were found (e.g. Physcia aipolia, P. dubia, P. tenella, Phaeophyscia sp., Melanelia exasperatula and Candelariella vitellina), with P. tenella (East Sayan) and M. exasperatula (West Sayan) as dominants. The results confirm that the distribution of lichen species on Abies sibirica twigs is a valuable indicator of current changes in atmospheric conditions.

The lichen Pyrenula minutissima is described as new to science from the Hyrcanian forests in northern Iran. In addition, three further, essentially tropical, Pyrenula species are reported for the first time from Iran. An identification key is provided for all eight Pyrenula species now known from Iran.

A new corticolous lichen species Ramonia variospora is described from Brazil. It has a verrucose thallus, concave, initally almost closed apothecia and variably 8 or c. 32–64, 1-septate ascospores per ascus; when 8 per ascus, ellipsoid and 16–22×6–10 µm; when c. 32–64 per ascus, broadly ellipsoid and 10–14×6–8 µm. A revised world key is given to all currently known species of Ramonia.

Phylogenetic analyses of nuclear (Mcm7, nrITS, nrLSU) and mitochondrial (mrSSU) DNA sequences revealed geographically disjunct lineages in Leptogium hibernicum. One of these lineages is described here as Leptogium krogiae, which differs from L. hibernicum in the thinner thallus (190–210 µm vs. 390–480 µm), shallowly striate lobes instead of deeply furrowed lobes, isidia that are seldom distinctly flattened, and apothecia with a subhymenial euparaplectenchymatous layer. Leptogium krogiae is a widespread epiphyte in mist-affected woodlands and montane forests in East Africa and appears to be a common species.

Arctomia teretiuscula sp. nov. (Arctomiaceae) is described from Sichuan Province, China. A minutely coralloid, bryophilous cyanolichen, it is a further example of the biogeographical link between the lichen biotas of the Himalayan region and the Arctic. A key to the three accepted species of Arctomia is provided.

The generic name Paralethariicola gen. nov. is introduced for a lichenicolous fungus very similar to Lethariicola, but differing by the presence of excipular hairs, asci with a hemiamyloid apical ring and a more flattened apex, curved or slightly helicoid ascospores with ± pointed ends, and thicker paraphyses. The single species, Paralethariicola aspiciliae sp. nov., is lichenicolous on Aspicilia, and is known from continental Spain and Sardinia.

The genus Thelopsis was classified in the family Stictidaceae but its systematic position has never been investigated by molecular methods. In order to determine its family placement and to test its monophyly, fungal DNA of recent collections of Thelopsis specimens was sequenced. Phylogenetic analyses using nuLSU, RPB2 and mtSSU sequences reveal that members of Thelopsis form a monophyletic group within the genus Gyalecta as currently accepted. The placement of Thelopsis, including the generic type T. rubella, within the genus Gyalecta challenges the generic circumscription of this group because Thelopsis is well recognized by the combination of morphological characters: perithecioid ascomata, well-developed periphysoids, polysporous asci and small, few-septate ellipsoid-oblong ascospores. The sterile sorediate Opegrapha corticola is also placed in the Gyalectaceae as sister species to Thelopsis byssoidea + T. rubella. Ascomata of O. corticola are illustrated for the first time and support its placement in the genus Thelopsis. The hypothesis that O. corticola might represent the sorediate fertile morph of T. rubella is not confirmed because the species is phylogenetically and morphologically distinct. Thelopsis is recovered as polyphyletic, with T. melathelia being placed as sister species to Ramonia. The new combinations Thelopsis corticola (Coppins & P. James) Sanderson & Ertz comb. nov. and Ramonia melathelia (Nyl.) Ertz comb. nov. are introduced and a new species of Gyalecta, G. amsterdamensis Ertz, is described from Amsterdam and Saint-Paul Islands, characterized by a sterile thallus with discrete soralia. Petractis luetkemuelleri and P. nodispora are accommodated in the new genus Neopetractis, differing from the generic type (P. clausa) by having a different phylogenetic position and a different photobiont. Francisrosea bicolor Ertz & Sanderson gen. & sp. nov. is described for a sterile sorediate lichen somewhat similar to Opegrapha corticola but having an isolated phylogenetic position as sister to a clade including Gyalidea praetermissa and the genera Neopetractis and Ramonia. Gyalecta farlowii, G. nidarosiensis and G. carneola are placed in a molecular phylogeny for the first time. The taxonomic significance of morphological characters in Gyalectaceae is discussed.

Degelia cyanoloma (Schaer.) H. H. Blom & L. Lindblom is resurrected from synonymy and elevated from varietal rank to species. The taxon was earlier referred to D. plumbea (Lightf.) P. M. Jørg. & P. James, however, several discontinuous character states distinguish the two species. Degelia cyanoloma is characterized morphologically by having a large thallus that is pale greyish when dry, lobes that are composed of consecutive trough-shaped segments with an upper surface without squamules, no isidia or soredia, and apothecia discs that are dark reddish brown to blackish. Degelia cyanoloma has a euoceanic distribution and is known from western Europe (Norway, France, Great Britain, Ireland, Portugal, Spain). Based on results from studies of morphology, we hypothesize that D. atlantica (Degel.) P. M. Jørg. & P. James is the closest relative of D. cyanoloma among the European species of the genus whereas D. plumbea is closely related to D. ligulata P. M. Jørg. & P. James.

Changes in the functional traits of the terricolous lichen Peltigera aphthosa with declining soil fertility during ecosystem retrogression were investigated. A well-documented retrogressive chronosequence of 28 forested islands in northern Sweden that differ greatly in fire history and which spans 5000 years was used. The abundance of cephalodia increased, indicative of higher N2-fixation rates resulting from lower N availability. Thallus δ13C values increased with ageing soils, in line with declining δ13C values of the humus substratum along this gradient. However, δ13C values were also driven by variation in factors that were at least partly independent of soil ageing. As such, δ13C values were mostly related to specific thallus mass (STM), possibly because a higher STM gives a thicker cortical layer and thus greater resistance to CO2 diffusion, leading to higher δ13C values. STM and other measured traits (i.e. thallus N, P, secondary compounds and water-holding capacity) were unresponsive to the gradient, despite these traits being very responsive to the same gradient in epiphytic lichen species.

The new species Lecanora ulrikii from Bhutan and Thailand is described. It belongs to Lecanora s. str. and is characterized by relatively large, orange-brown to brown apothecia that are constricted at the base, a clear to inspersed hymenium, an epihymenium of the glabrata-type, and by the presence of atranorin, usnic acid and the isoarthothelin chemosyndrome. Further, three species, L. arthothelinella, L. austrotropica and L. subimmergens, are reported for the first time from Thailand.

Twenty-five mainly crustose and saxicolous lichens are reported from the subalpine and alpine belts of Mt Changbai (n.-e. China, near the Korean border). All are new records to the lichen flora of the north-eastern provinces of China, 12 of them to the flora of all China, and four to the flora of all Asia. There is some floristic similarity to some other areas with cool humid climates in the Northern Hemisphere, e.g. Iceland.

The lichen floras occurring on high-level quartzite, Moine granulite, syenite and calcareous schist in the northern Highlands of Scotland are compared. Rock mineralogy is of overriding importance in determining the assemblages present, though this factor can be modified by extraneous nutrients. Local climatic conditions favour a cloud zone community dominated by ‘alectorioid’ species, produce stony ablation surfaces at a low level and allow maritime species to grow far inland. Ben Hope, with 34 ‘ rare ’ species recorded, is confirmed as a major site for alpine calcicolous lichens. Lecanora chlorophaeodes Nyl., a species new to Britain, is reported from the summit of Ben Loyal. In contrast, the extremely hard, acid, nutrient-deficient quartzite of Foinaven displayed a flora characterized by a very low species diversity.

The morphology, anatomy, ecology and distribution of Buellia tesserata and Dimelaena radiata are discussed. New data on their chemistry are given. The present study reveals a very close relationship between both taxa and consequently their different generic position is questioned. Buellia fimbriata is reduced to synonymy with Buellia tesserata.

The current delimitation of the family Physciaceae has been generally accepted since detailed descriptions of ascus characters allowed for a more natural circumscription of lichenized ascomycetes. The generic relations within the family are, however, still controversial and depend on the importance different authors attribute to specific morphological or chemical characteristics. The aim of this paper is to describe ascospore ontogeny and to test the present taxonomic structure of the family against a parsimony-based cladistic analysis, which includes three different scenarios of a priori character weighting. A study of ascospore ontogeny revealed two distinct developmental lines. One line revealed a delayed septum formation, which clearly showed transitions from spores with apical and median thickenings to spores without apical, but still well developed median thickenings, and to spores without any thickenings. In the second developmental line with an early septum formation again taxa with no thickenings, median thickenings, and both median and apical thickenings were found. Although these characters were constant at a species level, median wall thickenings especially varied among otherwise closely related taxa. In the cladistic analyses the current taxonomic structure of the Physciaceae was only obtained after the five character groups, namely morphology and anatomy of the vegetative thallus, conidiomata and conidia, morphology and anatomy of the apothecia, ontogeny of the ascospores, and secondary metabolites of the thallus, were given equal importance, and after a subjective a priori weighting further increased the weight of the three characters ‘conidial shape’, ‘presence of apical thickenings’, and ‘spore septation delayed’. This structure was not supported by a cladistic analysis with equally weighted characters but reflected the biased character weighting of the present day Physdaceae taxonomy. The taxonomic importance of conidial characters and of anatomical and ontogenetical spore characteristics need, therefore, a careful reconsideration in future.