The inhibitory action of aqueous extracts from detached podetia of heathland Cladonia spp. and leachates from transplanted Cladonia turfs was tested using seeds of Avena fatua, Calluna vulgans and Deschampsia flexuosa. Significant inhibitory effects were found for each species. Further evidence from a field experiment suggests that patches containing a mixture of Cladonia spp. can inhibit germination or establishment of vascular species, probably through both chemical and physical processes, and thus maintain intact lichen patches in otherwise closed heathland stands.

Ambient CO2 concentration (together with CO2 exchange and microclimate) was recorded every 30 min for 15 months for Lecanora muralis growing in the Botanical Garden Würzburg (Germany, northern Bavaria), a habitat on the outskirts of the city. Annual mean CO2 was around 17 ppm higher than the global average reported for the time of measurement (361 ppm; 1995/96), and daily values ranged from 317 to 490 ppm. Diel courses of CO2 could be classified into three different types. Type A, when CO2 levels rose overnight and then fell strongly to below global levels during the day, which predominated in the summer (about 75 of days); Type B, irregular diel courses occurred during all seasons with often very rapid changes apparently due to advective CO2 transport; Type C, CO2 concentration was typically almost stable at generally between c. 330 and 430 ppm which predominated in the winter (63 of days).

Under controlled conditions, CO2 saturation of net photosynthesis (NP) of L. muralis at optimal hydration and light occurred at around 1000 ppm. NP was also affected by low CO2 at limiting light and thallus water contents. Based upon these data, we estimated the improvement of NP of L. muralis due to transient increase of ambient CO2 (as compared with the global average) for one selected combination of environmental factors (nocturnal dew or frost). This combination is an important source of water for the lichen, resulting in 40 of its annual production and, especially in these situations, photosynthesis was increased by high ambient CO2 in the early morning under prevailing Type A conditions. After dew activation, light compensation point of NP occurred at an average concentration of 413 ppm and diel maxima of NP at 402 ppm. This allows a rough estimate that the transiently elevated CO2 increased the photosynthetic gain of the lichen after dew of 7, or an improvement to its annual carbon balance of about 3. Conditions, especially interrelationships between lichen hydration, light and CO2 are so complex that we are not yet able to extend our estimates to other environmental situations of photosynthetic activity of L. muralis.

Mongolia is one of the least densely populated countries of the world with 2·6 million people occupying an area of 1·5 million km2. A high proportion of the population and economy is concentrated in the capital Ulan Bator, which has 1 million inhabitants. Ulan Bator is characterized by its high elevation (1350 m), low precipitation (300 mm), high annual sunshine duration, and its location in a basin. The city is surrounded by mountain ranges to the north and to the south. Furthermore, it is the coldest capital of the world with an annual mean temperature of −3·7°C (Hilbig et al. 2004). Outside Ulan Bator and a few industrial areas, including a large copper plant near the second-largest city Erdenet, Mongolia’s air is extremely pure (ADB 2006). Therefore, Mongolia’s forests, which cover 10% of the country (Erdenechuluun 2006) harbour a rich epiphytic lichen vegetation (Cogt 1995). Most of these woodlands are conifer stands that form the southernmost range of the continuous Siberian taiga forests (Gunin et al. 1999). Eighty percent of the forest area of Mongolia is covered by Larix sibirica (Savin et al. 1978), while other important tree species in the taiga include Pinus sibirica, P. sylvestris, Picea obovata, Abies sibirica, and Betula platyphylla (Hilbig 1995; Dulamsuren et al. 2005). Dominant epiphytic lichen species in the larch-dominated taiga include Bryoria fuscescens, B. nadvornikiana, Evernia mesomorpha, Flavopunctelia soredica, Hypogymnia bitteri, H. physodes, Lecanora symmicta, Melanohalea septentrionalis, Parmelia sulcata, Usnea sp., and Vulpicida pinastri (Biazrov 1974; Hauck et al. 2007).

Two new genera and four new species of bulbil-forming basidiomycetes are described. Phylogenetic analyses of nuLSU and ITS sequences place them in Cantharellales. A facultative lichenicolous species with yellow to orange-yellow bulbils from South America groups with the type of Burgella and is consequently described as B. lutea. The new species and genus Burgellopsis nivea is introduced for material from Scotland with white bulbils overgrowing saxicolous lichens. An obligate lichenicolous species with particularly large, applanate bulbils developing over Peltigerales in South America could not be placed accurately using ITS sequences and is described as the new species and genus Bulbilla applanata. A European species with brown, facultatively lichenicolous bulbils grouped with Ceratobasidium and Thanatephorus species and is described as the new Ceratobasidium bulbillifaciens.

The crustose genus Staurothele (Verrucariaceae, Ascomycota) is a common component of the lichen flora from subneutral to alkaline silicate rocks in temperate to cold-temperate climates. Our field study in the karst system of northern Vietnam showed that it is also common on dry to humid limestone in the wet tropics. Molecular data revealed that species of Staurothele from Vietnam belong to an unnamed clade sister to the genus Endocarpon, together with the tropical Australian species Staurothele pallidopora and Staurothele diffractella, a North American species recently transferred to Endocarpon based on molecular data. The genus Willeya is here resurrected for this clade of crustose epilithic Staurothele with pale ascospores. Eight new combinations are proposed and three new species of Willeya are described from Vietnam. Sampling tropical members of a lichen family previously mostly known from temperate areas contributed significantly to improving its generic classification.

Lichenoconium christiansenii sp. nov. is described and illustrated from the apothecia of Nodobryoria abbreviata (syn. Bryoria abbreviata) in Washington State, USA. The species recalls L. lichenicola, but differs in the more subglobose conidia and the shorter conidiogenous cells as well as in occurring on a different host. A key to the 14 species now known in the genus is provided. Lichenoconium cargillianum is also reported from Letharia vulpina for the first time.

An ecological biogeographical perspective provides an understanding of the factors that shape the geographical distribution of organisms, their biodiversity and ecological speciation. Focusing on members of the lichen genus Solenopsora, which are strongly linked to a Mediterranean-type climate, we aimed to depict their environmental niches in the Apennine Peninsula. This area represents their ecological optima, as well as the biogeographical centre of distribution. On the basis of occurrences of Solenopsora congeners, we identified the key ecological factors that shape their environmental niches. Applying an ensemble approach, which merges the results of Random Forest, GLM and MaxEnt algorithms, suitability maps were developed. These are mainly influenced by geological substratum, temperature and precipitation. Occurrence of Solenopsora taxa seems to be mainly governed by low variability in diurnal temperature and tolerance to dryness, with precipitation in the range of 0–20 mm in the driest month and a minimum temperature of >5 °C in the coldest month. The sensitivity to diurnal temperature, an important indicator for climate change, suggests that the taxa confined to Mediterranean bioclimatic types (i.e. Solenopsora grisea, S. marina, S. olivacea subsp. olbiensis and S. olivacea subsp. olivacea) might be good indicators of climatic stability. The geological substratum was a strong limiting factor and separated the taxa into three groups: those growing on calcareous, siliceous and ultramafic substrata. Limited co-occurrence of species confined to one of the three categories suggests that the level of niche differentiation is on a microhabitat level. Accounting for ecological requirements, the taxa differ in their tolerance to sub-optimal conditions. The ecological niches of a sister subspecies pair with different reproduction strategies, fertile S. olivacea subsp. olivacea and sorediate S. olivacea subsp. olbiensis, overlap strongly. However, habitat suitability for S. olivacea subsp. olbiensis is greater in areas with higher precipitation in the driest month, whereas S. olivacea subsp. olivacea is more restricted to warmer and drier areas. We also report new regional records for Italy and the first records of S. cesatii in Serbia and Ukraine, and of S. liparina in Serbia.

Two-years' observation of Athelia arachnoidea lesions in the field showed that they are long-lived perennial structures. In the Sheffield area, central parts of lesions become recolonized by Lecanora conizaeoides only after secondary infection by the lichen parasite Lichenoconium erodens followed by an invasion of the green alga Desmococcus naegelii. A. arachnoidea is active only during the winter months probably as a result of the higher humidity. The role of the sclerotia remains obscure.

A new isidiate, xanthone-producing species, Rinodina chrysidiata, is described and compared in detail with R. xanthophaea, a species with which it co-occurs in eastern Asia. The two species have an identical chemistry but are clearly separated by their differing lichenized diaspores, thallus morphology and ascospore type.

Lecanora barkmaneana, a sorediate corticolous lichen belonging to the Lecanora subfusca group, is described as a species new to science on the basis of numerous sterile collections and two richly fertile collections. It is known so far only from the Netherlands, where it often grows on roadside trees. It seems to be spreading rapidly at nutrient-rich sites.

We assessed the taxonomy and phylogenetic relationships of Hawaiian species of the neotropical genus Lobariella. A single species was previously reported from the archipelago, the widespread neotropical L. crenulata. We targeted three loci of the mitochondrial and nuclear ribosomal rDNA gene cistron (mtSSU, nuLSU, ITS) and also performed a molecular clock analysis. Our results show that L. crenulata s. str. is seemingly present in the archipelago based on older herbarium collections. However, Hawaiian Lobariella includes three additional, presumably endemic, species unrelated to L. crenulata and new to science: L. flynniana Lücking, Moncada & C. W. Sm., with richly branched marginal phyllidia giving the thallus a fruticose appearance; L. robusta Lücking, Moncada & C. W. Sm., with a rather thick thallus and abundant, large, laminal phyllidia; and L. sandwicensis Lücking, Moncada & C. W. Sm., with a delicate thallus producing apothecia. Lobariella flynniana represents a novel morphotype within the genus, thus far known only from Hawaii. All three species are very closely related, forming a well-supported, monophyletic clade in spite of their morphological differences, suggesting local micro-radiation. Molecular clock analysis indicates that this clade colonized the islands between 1–8 mya and diverged between 0–2 mya. We interpret recent colonization as one of the main reasons why this clade has not diversified further.

Some definitions of the term ‘lichen’ have often emphasized the role of the mycobiont as exhabitant in the symbiosis. Mastodia tessellata and Turgidosculum ulvae, both forming lichen-like associations with foliose algae, have traditionally defied that definition. In this study, we delve into the poorly known association of T. ulvae with Blidingia minima. Using four molecular markers (nrLSU, nrSSU, RPB1, mtSSU) we show that T. ulvae is a member of the family Verrucariaceae, closely related to the marine species Verrucaria ditmarsica. The presence of bitunicate asci and single-cell ascospores is confirmed. Our analysis of a fragment of the rbcL marker demonstrates that the photosynthetic partner belongs to B. minima, although relationships within this taxon remain unclear. Transmission electron microscopy allowed us to illustrate how T. ulvae interacts with Blidingia cells, and how haustoria in that species differ from those previously investigated in other marine lichen-forming fungi.

Ten new species in nine different genera are described from the Falkland Islands (Islas Malvinas): Bryonora granulata with a finely granular thallus containing perlatolic acid; Bryoria mariensis, a terricolous species with norstictic acid and unusual cortex cells; Carbonea hypopurpurea with a K+ purple hypothecium and a thallus containing confluentic and 2′-O-methylperlatolic acids; Caloplaca megalariicola lichenicolous on Megalaria grossa; Cladonia flammea with a red-orange coloration on the lower side of the primary squamules; Cliostomum falklandicum, on rocks and with a dispersed thallus containing only atranorin; Lepraria malouina with usnic and stictic acids; Rimularia andreaeicola, over bryophytes and lacking lichen substances; R. subpsephota, similar to R. psephota but with a discrete white thallus lacking norstictic acid; and Usnea austrocampestris, a straggling species in sect. Neuropogon from the mountain tops. Rimularia andreaeicola is also known from Tierra del Fuego and R. subpsephota from Tierra del Fuego and South Georgia, but the other species are known only from the Falkland Islands. The new combinations Carbonea agellata, C. subdeclinans, Cliostomum aeruginascens and C. violascens are also made; Lecidea interrupta Darb. and Lecidea protracta Darb. are reduced to synonymy with Lecanora xantholeuca (Müll. Arg.) Hertel; Rhizocarpon simillimum is reported for the first time from the Southern Hemisphere, from the Falkland Islands and New Zealand; and Bryoria chalybeiformis is reported for the first time from the Falkland Islands.

We studied ascospore dispersal and ontogeny in several species of Trypetheliaceae and one species of Graphidaceae with megalosporous (very large) ascospores, including Aptrootia terricola (Aptroot) Lücking, Umaña & Chaves, Architrypethelium nitens (Fée) Aptroot, A. seminudum (Mont.) Aptroot, Astrothelium diplocarpoides Müll. Arg., Laurera gigantospora (Müll. Arg.) Zahlbr., and Ocellularia subpraestans Hale. Although mature ascospores are very different among species of Trypetheliaceae, all species studied share plesiomorphic ontogenetic features such as the formation of a single central euseptum and subsequent development of a variable number of transverse distosepta with diamond-shaped lumina (astrothelioid ascospore type). Even the dark brown, richly muriform ascospores of Aptrootia terricola go through an astrothelioid stage. This suggests that ascospore types may be more closely related than suggested by their mature morphology, and could explain why related taxa can develop markedly different ascospore types. We discuss the implications for systematic classification of Trypetheliaceae in the light of recent molecular studies, and also speculate about the ecological importance of large ascospores, especially with muriform septation.

Dermatocarpon luridum is a subaquatic lichen which is distributed within temperate climatic zones around the world. It colonizes rock substrata along the shoreline of lakes and rivers of watersheds that regularly experience water level fluctuations. The mycobiont produces perithecia with small, simple spores that are thought to be wind dispersed. The photobiont, Diplosphaera chodatii, occurs both free-living and lichenized but little is known about its distribution and dispersal. The goal of this study was to compare the population structure of the photobiont from lakes and rivers in central North America with those of Europe. Specimens were collected in Manitoba, Canada and Austria. Population structure of the algal symbiont was assessed using the internal transcribed spacer (ITS) of ribosomal DNA (rDNA) and actin gene sequences. Results showed that genetic diversity and gene flow was high within local populations, but gene flow was low between continental populations. Low levels of gene flow between the most distant populations support the isolation-by-distance theory. The photobiont on both continents is also reported to be the photobiont for other lichen species contributing to photobiont availability for D. luridum.

Niesslia echinoides Etayo, Flakus & Kukwa sp. nov. is described from Bolivia from the corticolous thallus of Erioderma barbellatum. The fungus is characterized by large ascospores usually breaking into halves within the asci, strongly setose and aggregated ascomata, usually simple setae, and no damage caused to the host thallus.

Eight new species of Lecideaceae are described from the southern subpolar region: Bryobilimbia coppinsiana Fryday, a saxicolous species with one septate ascospores (Campbell Island, New Zealand); Immersaria fuliginosa Fryday, with a thallus composed of thalloconidia (Falkland Islands); Lecidea aurantia Fryday, with an orange thallus (Auckland Islands, New Zealand); L. campbellensis Fryday, with an endolithic thallus and apothecia resembling those of a species of Porpidia (Campbell Island); Poeltiaria ochyrae Hertel, which is similar to P. subincongua but with a thick areolate thallus (South Orkney and South Shetland Islands); P. tasmanica Fryday, which is similar to P. urbanskyana but with smaller ascopores (Tasmania); Poeltidea inspersa Fryday with an enolithic thallus and a hymenium with large oil globules (Falkland Islands); and Porpidia vulcanoides Hertel & Fryday with immersed apothecia with a thick margin and large ascospores (SW Chile). Lecidea kalbii Hertel is resurrected from the synonymy of L. mannii Tuck. and treated as a distinct species. The circumscription of genera within the Lecideaceae is also discussed: Poeltiaria is shown to be heterogeneous, and the genera Labyrintha and Notolecidea are reduced to synonymy with Poeltidea and Poeltiaria respectively, and the new combinations Poeltidia implexa (Malcolm et al.) Hertel & Fryday and Poeltiaria subcontinua (Hertel) Hertel & Fryday made. A key to the genera of Lecideaceae s. lat. is provided.

Species of Usnea with black pigmentation in the cortex and dark apothecial discs are informally referred to as neuropogonoid lichens. Here we studied the phylogenetic relationships of the core group of neuropogonoid lichens using DNA sequence data of three loci: nuclear ITS and IGS rDNA and RPB1. Maximum likelihood and Bayesian analyses revealed monophyly of 11 neuropogonoid species, with U. ciliata and U. subcapillaris forming a separate lineage. The backbone of the phylogeny of the core group was not resolved with statistical confidence, but relationships of groups of two to three species received strong support (U. acromelana +U. aurantiaco-atra; U. messutiae+U. pallidocarpa; U. sphacelata+U. subantarctica+U. trachycarpa; U. lambii+U. perpusilla+U. ushuaiensis). The new combination U. lambii (Imshaug) Wirtz & Lumbsch comb. nov. is made and U. messutiae Wirtz & Lumbsch sp. nov. is described.

The new genus Coniarthonia is described to accommodate a group of species previously placed in Anhonia and Arthotheliwn. Crystallized red pigments that are distributed throughout hydrophobic ascomatal structures are characteristic of the new genus, which includes species with both muriform and transversely septate ascospores. Coniarthonia erythrocarpa, C. gregarina, C. pulchernma, C. pyrrhula and C. ivilmsiana are new combinations, and C. haematodea is new to science. Two subgroups are distinguished in the genus: the C. pyrrhula group, with larger ascospores, and the C. pulckcrruna group, which has comparatively small, one-septate ascospores. The reddish compounds are characterized by TLC. A key to the species is provided.