Ramalina species are among the most abundant lichens on the Galapagos Isles. A total of fifteen species have been distinguished, four of which are described as new here: Ramalina darwiniana, R. fragilis, R. furcellangulida and R. polyforma. These new species are considered to be endemic to the Galapagos whereas previous reports refer to relatively common, more widely distributed species. Several other species are reported here for the first time from the Galapagos.

Thelopsis paucispora is described as new from Socotra (Yemen, Indian Ocean). The species is characterized by asci containing 30–40, two-celled spores, Trentepohlia as photobiont and a crustose subeffigurate thallus colonizing calcareous rock. A key for all known species of the genus Thelopsis is provided.

Zwackhiomyces cervinae Calat., Triebel & Pérez-Ortega is described as new to science from Spain and Iran. This lichenicolous species grows on the lateral side of the squamules of Acarospora cervina, and it is characterized by its relatively large ascospores, which are brown when overmature. It is compared with several Zwackhiomyces species and with other taxa sharing some of its characters. A key to all the known species of the genus is also provided.

The taxonomic and nomenclatural status of the common Scutula (Ramalinaceae, Lecanorales, Ascomycota) parasitizing species of Solorina (Peltigeraceae, Lecanorales) is clarified. The type of Biatorina tuberculosa Th. Fr., which, according to the protologue, was described from a Peltigera, is actually growing on Solorina saccata, and the correct name for this species is here shown to be Scutula tuberculosa (Th. Fr.) Rehm. Lectotypes are designated for Lecidea solorinaria Nyl., Scutula krempelhuberi Körb. and Lecidea solorinicola Vain. Notes on the taxonomy and classification of the genus are given, and a key to the species of Scutula s. str. in the Northern Hemisphere is presented. Scutula tuberculosa is reported as new to Asia and North America.

%The new saxicolous species P. clercii Messuti & A. W. Archer is described. The following two taxa are reported for the first time from Africa: P. petrophyes C. Knight and P. subventosa var. deficiens A. W. Archer & Elix. A brief description of each species is given together with notes on their chemistry, distribution, ecology and taxonomy.

Xanthoparmelia perezdepazii from the Canary Islands is described as new to science. It is characterized by an isidiate upper surface, the presence of usnic, constipatic and protoconstipatic acids in the medulla and a brown lower surface.

Opegrapha invadens Etayo on Pannaria farinosa and Plectocarpon usneaustralis Etayo on corticolous Usnea sp. are described as new from southern Chile.

The new species Ramboldia blastidiata Kantvilas & Elix, from Tasmania and mainland Australia is described, and the new combination, R. elabens (Fr.) Kantvilas & Elix is proposed. The South American R. petraeoides var. concava (Müll. Arg.) Fryday is considered a synonym of R. petraeoides (Nyl. ex C. Bab. & Mitt.) Kantvilas & Elix s. str., and R. crassithallina Kalb and R. sorediata Kalb, both previously considered endemic to Western Australia, are recorded from Tasmania for the first time. A key to the 11 species of Ramboldia is presented.

The diminutive species Gyalidea fruticola is described from Central Sweden and northern Italy. It is typically found on decaying bark, on semi-shaded Lonicera spp. in deciduous, mixed deciduous/coniferous or coniferous forests. The species is characterized by its small and pale apothecia, its submuriform ascospores and its habitat preference.

Buellia peregrina is described as new to science from small limestone pebbles on exposed ground of the coastal Namib Desert, Namibia. The species is unusual for two reasons: (1) it is the only species in Buellia s.l. currently known to grow euendolithically, i.e., establishing a thallus entirely within its rock substratum, and (2) its apothecia contain a previously unknown blue pigment, here described as peregrina-blue according to its colour and characteristic reactions with HNO3, KOH and HCl.

Three new Xanthoria species are described from South Africa. Xanthoria hirsuta sp. nov. has hairs on the surface of the thallus and apothecia, best visible in young, growing parts. Dust particles and sand granules stick to this hairy surface, giving the thallus a somewhat dirty appearance. Xanthoria inflata sp. nov. has inflated lobes similar to a Menegazzia. It carries numerous crystals on its medullary hyphae, which are ivory-coloured in young, but intensely orange coloured in old lobes. Xanthoria doidgeae sp. nov. has relatively small lobes with pruinose margins. All three species are fertile, none of them forms symbiotic propagules.

Lecidea rubrocastanea T. Sprib. & Printzen is described as new from conifer bark and wood in montane valleys of inland British Columbia, Idaho, Montana, Oregon and Washington State. It is characterized by its combination of a crustose olivaceous thallus lacking secondary lichen substances, small, dark burgundy-red or maroon apothecia, dark-capped paraphyses, Lecidella-type ascus, small, thin-walled ascospores, and bacilliform conidia. The generic affinities of the species based on analysis of ITS DNA are unclear, but it has numerous morphological traits in common with Japewia.

Opegrapha species with muriform ascospores are revised and two species, differing only in the shape of their excipulum, are accepted: O. arabica, a widespread coastal species, and O. varians, known from mainland Yemen and Socotra. The genus Dictyographa, previously distinguished from Opegrapha by its muriform ascospores, is reduced into synonymy with Opegrapha. Dictyographa angolensis and D. sandwicensis are new synonyms of O. arabica; the type of D. cinerea was found to be a mixture of different species of the Hysteriaceae; and D. contortuplicata and D. psyllocarpa are excluded from the Arthoniales. Lectotypes are designated for D. angolensis, D. contortuplicata and D. sandwicensis.

A new species of lichen, Graphis sundarbanensis, is described from India. It is characterized by ascomata with a pruinose wide-open disc, a laterally carbonized apically convergent exciple and 6–8 locular halonate ascospores.

A taxonomic investigation of Lethariella smithii and L. zahlbruckneri has established that they are conspecific. Three chemical races are recognized: race 1 containing norstictic acid, race 2 norstictic acid and placodiolic acid, and race 3 placodiolic acid as major medullary substances.

One new species and 71 new records are reported from Thailand. Coenogonium disciforme sp. nov. is distinguished by its disc-shaped, shortly stipitate isidia, which leave perfectly circular holes, almost like punched holes, when detached.

The lichenicolous Phoma species on Cladonia are revised. A statistical analysis of the conidial size suggests that three species are involved: P. cladoniicola sp. nov. a common and widespread species in the Northern Hemisphere occurring on a wide range of Cladonia species; P. foliaceiphila sp. nov. known from C. foliacea and C. fimbriata in Europe; and P. grumantiana sp. nov. known from C. symphycarpia and C. mateocyatha in Svalbard and the USA.

A detailed chemical and morphological study has been carried out on West European specimens of Cladonia subulata (L.) F. H. Wigg. and C. rei Schaer. Using thin-layer chromatography (TLC), three different chemotypes were found, which did not show any correlation with distribution, substratum, habitat or any of the morphological characteristics mentioned in recent floras. Moreover, the application of UV (long-wave) proved to be unreliable for detecting homosekikaic acid and thus for distinguishing the two species. It appears that only one species, with three chemotypes, exists in Western Europe. Cladonia subulata is therefore another of the more than ten Cladonia species reported so far that can contain either homosekikaic and/or fumarprotocetraric acid.

The new species Diploschistes elixii is described from Western Australia. It is characterized by perithecioid ascomata and large ascospores. It resembles D. hensseniae but is readily distinguished by larger ascospores (up to 45 μm), having lecanoric acid as major constituent, and an epruinose thallus surface. It is currently known from several localities in south-western Australia, where it grows on soil.

Chlorophyll a fluorescence was measured every three months from December 2003 to December 2004 in ten, randomly selected thalli of the epiphytic lichen Punctelia subrudecta (Nyl.) Krog occurring in a deciduous, thermophilous downy oak wood in southern Tuscany (central Italy). In situ measurements were carried out with a photosynthesis yield analyser Mini-PAM (Walz, Effeltrich, Germany) on the same measuring points of 30-minute dark-adapted, fully hydrated thalli. The results show a remarkable seasonal change in Fo, Fm, and Fv/Fm, probably caused by a long-term physiological-structural adaptation of the photobiont to the gradual modification of the climatic conditions of each measurement period and the light regime of the understorey. However, P. subrudecta is also sensitive to rapid changes in microclimatic conditions as the PSII functionality is affected by the light regime of the days preceding the field measurements. Some critical observations on the statistical analysis of chlorophyll a fluorescence parameters are also made.