Lichen material from the Iberian Peninsula of Melanelia commixta, M. hepatizon and M. sorediella has been studied and compared on the basis of morphology, chemistry, habitat and distribution. The new combination Melanelia sorediella is proposed and Cetraria commixta f. sorediella is lectotypified. Chemotypes I and III have been detected in M. commixta. Melanelia sorediella is characterized mainly by the formation of pycnoisidia and soralia-like structures in the lamina and margins of the thallus and by the absence of pseudocyphellae and apothecia. The pycnoisidium is here described as a combination of isidia-like proliferations of the thallus surface containing pycnidia, carrying algae and acting as vegetative symbiotic propagules. Non detached pycnoisidia grow into lobuli in central parts of the thallus, regenerating it. Pycnoisidia, soralia-like areas and lobuli are formed as a consequence of pycnidia development. Melanelia sorediella is morphologically and chemically close to M. commixta and is currently known from mountains of central and south-west Europe where it grows on acid rocks. In south-western Europe, the meridional limit of the distribution of the three species studied seems to be located in the mountains of the central part of the Iberian Peninsula (Sistema Central Ibérico). Relevant data on the three species are provided and a key is also included.

Two new species of the small genus Crypthonia are described from the Chapada do Araripe, an isolated table mountain in the state of Ceará, in NE Brazil. Both share the thallus and ascoma organization with the other known species of the genus, and are mainly characterized by differences in ascospores and chemistry. Crypthonia lichexanthonica A. A. Menezes, M. Cáceres & Aptroot has 7-septate ascospores and contains lichexanthone in the thallus, and C. submuriformis A. A. Menezes, M. Cáceres & Aptroot has (sub)muriform ascospores and also contains lichexanthone, but only in the ascigerous areas. A key to all known species of the genus Crypthonia is provided, in which Crypthonia olivacea Frisch & G. Thor is newly reported from Argentina. The new species Syncesia byssolomoides A. A. Menezes, M. Cáceres & Aptroot is described from the same area. It also has a thin byssoid thallus, but differs by the narrowly fusiform ascospores and by containing psoromic acid. It differs from all Syncesia species by the absence of carbonization and the presence of psoromic acid. The epiphytic lichen flora in this Caatinga forest area is dominated by crustose lichens, with Graphis and Polymeridium as the most speciose genera.

In the framework of ongoing studies on tropical representatives of Bacidiasensu lato, six species so far included in that genus are transferred to Fellhanera: Fellhanera Africana(Vězda) Lücking comb. nov. (Bas.: Bacidia Africana (Vězda), Fellhanera albidocincta Vain.) Lücking comb. nov. (Bas.: Bilimbia albidocincta Vain.), Fellhanera fragilis (Vězda) Lücking & Kalb comb. nov. (Bas.: Bacidia fragilis (Vězda), Fellhanera mastothallina (Vain.) Lücking & Serus. comb.nov. (Bas.: Bacidia mastothallina Vain.), Fellhanera naevia(Vain.) Lücking & Caceres comb. nov. (Bas.: Bacidia naevia Vain.), and Fellhanera submicrommata (Vězda) Lücking & Kalb comb. nov. (Bas.: Bacidia submicrommata Vězda). Fellhanera angustispora Lücking is reduced into synonymy with F. naevia.

Sixteen species of lichenicolous fungi are documented from Siphula-like lichens. Two new genera based on new species are introduced. Amylogalla Suija, Motiej. & Kantvilas, characterized by I+ blue, K/I+ violet vegetative hyphae and ascomatal wall, immersed, cleistohymenial, yellowish to orange ascomata, unitunicate, non-amyloid, 8-spored asci and hyaline, ellipsoid, aseptate ascospores, is described from Parasiphula in Tasmania. Saania Zhurb., characterized by superficial, stromatic, multilocular ascomata, non-amyloid hymenial gel, persistent periphysoids, bitunicate, non-amyloid, 4(–8)-spored asci and narrowly obovate to ellipsoid, 1(–3)-septate, initially hyaline and smooth-walled, later sometimes brown and verruculose ascospores, is described from Siphula in South Africa. Four additional species are described as new: two from Siphula (Cercidospora santessonii Motiej., Zhurb., Suija & Kantvilas and Stigmidium kashiwadanii Zhurb.) and two from Parasiphula (Endococcus hafellnerianus Motiej., Suija & Kantvilas and Pyrenidium macrosporum Motiej., Zhurb., Suija & Kantvilas). Additional hosts and/or expanded geographical ranges are reported for Aabaarnia siphulicola, Epigloea soleiformis, Plectocarpon gayanum and Pyrenidium actinellum. The Southern Hemisphere is the centre of species richness for siphulicolous fungi, with 12 species restricted to this region. Taxa recorded for the Northern Hemisphere are Sphaerellothecium siphulae (arctic and boreal) and the subcosmopolitan Epigloea soleiformis and Pyrenidium actinellum, both of which are also known from various lichen hosts. The distribution of siphulicolous fungi strongly underpins the current generic classification of Siphula-like lichens, with five species being confined exclusively to Parasiphula and nine to Siphula. A key to the taxa occurring on Siphula and Parasiphula is provided.

Three species are added to the recently reintroduced genus Tetramelas, T. chloroleucus comb. nov., T. confusus sp. nov. and T. granulosus comb. nov. Tetramelas confusus was first reported under the name of Buellia papillata but is more similar to T. insignis. Distinguishing characters are given in a Table. Tetramelas poeltii is reduced to synonymy with T. chloroleucus.

This paper, based on data from the latest checklist of Italy, analyzes the distribution patterns of rare and common lichen species within biogeographically homogeneous versus heterogeneous areas of Italy, and the relationships with some main drivers of rarity and commonness. The following data were used: 1) commonness-rarity values of 2565 species in nine ecoregions; 2) frequency of 353 nationally rare and 387 nationally common species in 21 administrative regions. The following functional and ecological traits were considered: growth form, photobiont(s), type of reproduction, substrata, bioclimatic range, ecological indicator values for aridity and eutrophication, and poleophoby. Within each ecoregion, rare species by far outweigh common species but about one third of these are common in other ecoregions. At the level of regional floras, rarity is significantly associated with epiphytic substrata, non-trebouxioid photobionts and high air humidity, while commonness is associated with saxicolous substrata, trebouxioid photobionts and eutrophication. Rarity seems to mainly depend on two factors, bioclimate (many rare species are outside the limit of their bioclimatic optima) and reduced availability of suitable habitats (e.g. old-growth forests), while commonness is mainly related to disturbance (eutrophication, creation of drier habitats). Most of the nationally rare lichens belong to an oceanic-suboceanic element with tropical affinities or to a small set of continental species with their optima in the dry steppe biome, which suggests that many rare species can persist in microrefugia, that is sites with microclimates that support small populations of species beyond the boundaries of the climatic limits of their main distributions.

Gneiss inselbergs in the Caatinga region of Ceará in equatorial Brazil are literally covered with a wide diversity of caloplacoid lichens. This includes two closely related new saxicolous species of Caloplaca, both with the aspect of a Lecanora of the subfusca-aggregate: C. lecanorocarpa has a grey areolate bullate thallus with atranorin on a black prothallus, grey thalline apothecium margin, sessile apothecia with glossy dark brown disc, and ascospores of 10–12×5·0–5·5 μm, with a 5·0–5·5 μm thick septum; and the similar, related C. lecapustulata which mainly differs by the rimose thallus with irregular mushroom-shaped pustules. The phylogenetic position of the two new species has been assessed to be within the Caloplacoideae. A key to all tropical lecanoroid Caloplaca species is provided.

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.

The new genus Halegrapha is introduced, with six species (five new species and one new combination) from Australia, the Philippines, Malaysia, Kenya, Mexico, and the United States: H. chimaera Rivas Plata & Lücking (type species; Philippines), H. floridana Common & Lücking (United States: Florida), H. intergrapha Hale ex Lücking (Malaysia), H. kenyana Kalb & Lücking (Kenya), H. mexicana A. B. Peña & Lücking (Mexico), and H. mucronata (Stirt.) Lücking (Australia). The genus resembles Graphis morphologically in the strongly carbonized, black lirellae and white-grey thallus strongly encrusted with calcium oxalate crystals, but has a Phaeographis-type hymenium (clear in two species) and ascospores, making it a ‘chimera’ between the two genera. Molecular data suggest the genus to be closely related to Phaeographis and allies but genetically distinct from any of the genera currently recognized, including Platygramme.

Lecidea fuscoatra (L.) Ach. is one of the earliest lichen species described, and is very common and widespread in Europe. Lecidea grisella Flörke, described from Germany, was kept separate at species level in many floras until the 1950s. In recent lichen floras, however, and in the most recent key to the genus (Hertel 1995), L. grisella is no longer accepted at species level, although it is keyed out and recognized by Hertel as L. fuscoatra var. grisella (Floerke) Nyl. The main difference is usually reported to be the thallus colour; brown and shiny in L. fuscoatra, grey and opaque in L. grisella. Some authors, for example Hertel (1995) and Wirth (1995), report that the two taxa have different habitat preferences: L. fuscoatra occurring mainly on acid substrata, while L. grisella is reported to prefer more neutral, often dust-impregnated rock and to be common on roof tiles.

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.

The genus Sagenidiopsis gen. nov. of uncertain family in the order Opegraphales is erected for a byssoid lichen which occurs in the cool temperate rainforests of the Macpherson Range of eastern Australia, S. merrotsii sp. nov. The genus is characterized by its byssoid thallus and bitunicate asci which have no amyloid structures apparent in the tholus. A byssoid thallus is without taxonomic significance at the family level, but is an ecological key character.

Trees have a crucial importance in the functioning of ecosystems on Earth. They are among the largest and longest-living taxa and provide habitat and shelter to numerous species belonging to diverse groups of organisms. Relict trees are of particular interest through their history of survival and adaptation, and because they potentially shelter rare or threatened organisms today. We investigated for the first time the diversity and distribution of epiphytic lichens and bryophytes found on the Cretan (Greek) endemic and relict phorophyte Zelkova abelicea (Ulmaceae). Our results showed that Z. abelicea hosts a high number of epiphytes. The Levka Ori mountain range in western Crete seems to be a hot spot for epiphytic lichens on Z. abelicea. Bryophytes had the highest diversity on Mt Kedros in central Crete but were absent from several other sites. Moreover, 17% of the studied lichens were recorded for the first time for Crete and 5% have never been recorded for Greece. Geographical position and browsing intensity seem to be important factors influencing the epiphytic community encountered. Tree morphology (dwarfed or arborescent) was also significant in influencing community composition although it was not possible to dissociate this factor from the effect of topography. Dwarfed individuals were found to have as much epiphytic diversity as arborescent trees. Ecological indicator values showed that high epiphytic diversity was found in some sites despite signs of eutrophication and disturbance due to pastoral activities and suggest the co-occurrence of both disturbance tolerant and sensitive species. Our results show how little is known about the biodiversity of Cretan phorophytes and highlights the need for further research on the topic.

The new species Calvitimela austrochilenis Fryday and Tephromela superba Fryday are described: the former from several collections from southern Chile and one from Marion Island, and the latter from southern South America (including the Falkland Islands), Campbell Island, (New Zealand), and Antarctica. Four new combinations are also made in Tephromela: T. atrocaesia (Nyl. ex Cromb.) Fryday from Îles Kerguelen, Heard Island, South Georgia, and southern South America; T. atroviolacea (Flot.) Fryday from southern South America and Îles Kerguelen; T. lirellina (Darb.) Fryday from only southern South America; and T. skottsbergii (Darb.) Fryday, which is shown to be an earlier name for T. austrolitoralis (Zahlbr.) Kalb & Elix, from throughout the region. Lectotypes are selected for Lecanora atrocaesia and L. atroviolacea. The systematic placement of Tephromela eatonii (Cromb.) Hertel from Kerguelen, Marion Island and Bouvetøya is also discussed but the species is retained in Tephromela.

The taxonomy of species related to Verrucaria praetermissa is investigated using morphological and molecular data. Verrucaria devensis is closely related to V. praetermissa but distinguished by the darker colour, the thinner and more uneven thallus, and the ITS sequence. This species is based on Leucocarpopsis devensis G. Salisb., which was originally described as the type species of a monotypic genus differing from Verrucaria by the absence of dark pigment. Verrucaria lapidicola is a new species from stones in non-aquatic situations; it is related to V. praetermissa and V. elaeina but differs in the very thin thallus and ITS sequence.