The genus Coppinsia (lichenized Ascomycetes, Agyriaceae) with the single species C. minutissima sp. nov. is described as new from the British Isles. This minute lichen occurs on soil and bryophytes in metal-rich habitats. It is characterized by a minute thallus, biatorine apothecia with an almost reduced but generally cupulate exciple, slightly branched and apically unthickened paraphyses, a Trapelia-type ascus, and non-septate, ovoid ascospores.

The morphology and the anatomy of the 13 species presently included in the genus Fulgensia were surveyed. Caloplaca aurea and C. paulii, two speciesregarded as closely related to Fulgensia by earlier authors, were also included in the study. Fulgensia was found to exhibit a great variation in both morphology and anatomy. The differences in size, shape and septation of the spores, in the anatomy of cortex and exciple, and in the gross morphology, will presumably motivate a different taxonomic treatment in the future. A tentative separation of the species into four different groups is proposed here. Group A comprises F. australis and F. chanousiae, which appear close to species in Caloplaca sect. Gasparrinia. Groups B and C, each comprises one species, F. schistidii and F. canariensis respectively and group D comprises the remaining nine species, including the type species F. fulgens. The last group may be further split by a more detailed investigation. The present separation of Fulgensia into two subgenera cannot be regarded as taxonomically sound. The genus is probably polyphyletic and the different groups are probably related to different groups within the large genus Caloplaca.

Lichen mycobionts are typical representatives of their fungal classes but differ from non-lichenized taxa by their manifold adaptations to symbiosis with a population of minute photobiont cells. Most interesting are the morphologically complex macrolichens, the fungal partner of which competes for space above ground and contains photobiont cells optimally positioned for gas exchange and illumination. Such thalli are the product of an amazing hyphal polymorphism, with multiple switches between polar and apolar growth and hydrophilic or hydrophobic cell wall surfaces. Hydrophobic sealing of the apoplastic continuum between the partners by means of mycobiont-derived hydrophobic compounds canalizes the fluxes of solutes during the often quite dramatic de- and rehydration processes and keeps the algal layer gas-filled at any level of hydration. The impressive tolerance of drought, heat and cold stress of most lichen-forming fungi and their photobionts is due to a very interesting combination of protective and repair mechanisms at the cellular level, the molecular bases of which remain to be explored. Contemporary experimental lichenology is analysed and strategies are proposed aimed at better integration into mainstream biology.

The species of Dermatocarpon occurring in the British Isles are reviewed, with special reference to the hydrophilous species; a number of related species not yet recorded for the British Isles are also briefly treated. Dermatocarpon deminuens and D. leptophyllodes are confirmed as British; the name D. leptophyllum should be deleted from the British list. The name D. melophyllum is shown to be based on discordant elements. A key is provided to the British and Irish species.

Biatora hertelii Printzen & Etayo and B. troendelagica Holien & Printzen are described as new to science. Diagnostic characters, systematic affinities, ecology and distribution of both species are briefly discussed. Divaricatic acid is reported for the first time from a species of Biatora

Felihanera viridisorediata Aptroot, Brand & Spier, a corticolous sorediate species commonly found sterile, is described from fertile material on Juglans glabra in the Netherlands. It was also found with apothecia on, for example, twigs of Vaccinium myrtillus, Lonicera, and other trees. It seems to be common and rapidly spreading in sheltered habitats in Belgium, Germany and the Netherlands, also occasionally on wood, roofs, granite and brick. It is close to other Felihanera species, especially F. seroexpectata and F. viridis, but it differs in the paler soredia, smaller, 1-septate and constricted ascospores and the presence of roccellic acid.

Molecular biological techniques now provide many opportunities for determining relationships between organisms. In lichen-forming fungi, polymerase chain reaction (PCR) amplification can be undertaken with primers that have enhanced specificity for fungi, allowing the recovery of precise regions of the genome of the fungal partner. Such PCR techniques are suitable for the analysis of both fresh and dried specimens of great age, and as the techniques require only minimal amounts of starting material, they are suitable for the analysis of large numbers of specimens. PCR can be used to examine both conserved and variable regions of the fungal genome that may be taxonomically significant, and variability in these sequences can be used to describe species boundaries. The ease of analysis of large numbers of specimens without the need to purify or culture the fungal partner makes analysis and comparison of infra- and inter-specific relationships possible, and provides valuable information into their genetic background. Most molecular analyses undertaken with lichen-forming fungi have considered variation within ribosomal RNA clusters, and in this paper we consider the application and interpretation of such PCR-based analysis in the circumscription of species and in determining concepts for individuality and infra-specific groupings.

Two Parmeliella-like lichen species are described as new: Santessoniella pulchella, known from warm temperate parts of eastern Australia and northern New Zealand, and Siphulastrum squamosum, a relatively common species on stumps ofNothofagus in southern Chile. Both differ from Parmeliella s. str. in the hemiamyloid, finally red-brown hymenial iodine reaction and the apical structures of the asci, as well as in thallus details (anatomy and chemistry). Parmeliella major Darb. is a synonym of P. thysanota (Sirt.) Zahlbr., which thus proves to be a circumpolar species in the Southern Hemisphere, though not yet discovered in South Africa. A new species, Parmeliella lacerate, is described from the Republic of South Africa, and related to Parmeliella chilensis (Hue) P. M. Jørg., comb. nov.

Twenty species of lichenicolous ascomycetes are recorded for the western Pyrenees. Capronia hypotrachynae Etayo & Diederich (on Hypotrachyna species, also known from the Canary Islands and from Papua New Guinea), Llimoniella pubescens Etayo & Diederich (on Lepraria species, also from Scotland and Papua New Guinea), Polycoccum microcarpum Diederich & Etayo (on Cladonia species, also from Scotland), Skyttea megalosporae Etayo & Diederich (on Megalospora tuberculosa), Sphaerellothecium cinerascens Etayo & Diederich (on Cladonia parasitica) and S. parmeliae Diederich & Etayo (on Parmelia s. str., also from Finland) are described as new.

Gyalideopsis cochlerifer Lücking & Sérus. sp. nov. is a new, pantropical, commensalistic species restricted to foliicolous representatives of certain genera in the Gomphillaceae. It produces black spathulate hyphophores and small black apothecia.

Practically most of the taxonomists working on vascular plants and fungi are using the so-called taxonomic species concept, relying largely on morphological criteria or other observable patterns of discontinuity and assuming that these patterns are reflecting the underlying genetic integrity of species. Such a concept is described in detail here for the genus Usnea. The typologicalview versus the populational view of species are discussed. The diagnostic value of characters used by previous and recent taxonomists of the genus is analysed. The fact that Usnea has such a bad taxonomic reputation is discussed. The use by J. Motyka, author of the world monograph published in the thirties, of characters that are strongly modified by environmental factors together with a typological view of species are thought to be mainly responsible for this. More than 770 names have been published worldwide so far and it is suggested that around 50% are to be considered as synonyms.

Lichenicolous fungi on species of the genera Baeomyces, Dibaeis, and Icrnadophila in Norway include Acarosporium lichenicola Ihien & Tonsberg sp. nov., Cercidospora parva Hafellner & Ihlen sp. nov., Phoma macuhformans Ihien sp. nov., Micarea inquinans (reported new to Scandinavia), Arthrorhaphzs vacillans, Pyrenzdzum actinellurn s. lat., Sphaerellotheciurn coniodes (all new to Norway), Arthrorhaphzs alpina, A. citrinella, A. grisea, A. rnuddii, Dactylospora athallina, D. attendenda, Epilichen glauconigellus, E. scabrosus, Stigmidium icmadophilae, Thelocarpon epibolum, and T. lichenicola. Their anatomy and morphology are described, and a key to the taxa provided. Host preferences are discussed, and distribution maps are provided for the obligately lichenicolous fungi and those that also occur autonomously.

Between 1960 and 1975, 212 names of foliicolous lichenized fungi (or believed to have such a biological status) were described or used by A. C. Batista and co-workers. A considerable number of the new names were not validly published but mentioned as nomina nuda in various papers, while a further 69 names exist only as herbarium names. A taxonomic revision demonstrates that 36 of the 38 validly described genera ( = 95%) and 56 of the 68 validly published species and varieties ( = 82%) are either synonyms of previously known taxa, or represent non-lichenized or lichenicolous fungi, or cannot be readily identified and remain nomina dubia. Most of the descriptions refer to pycnidia, particularly those of the Strigulaceae (5 genera, 8 species or varieties), the hyphophores of Gomphillaceae (6 genera, 10 species), and the genus Microtheliopsis (3 genera, 3 species), whereas campylidia of the Ectolechiaceae are under-represented. A further six, monotypic genera correspond to lichenicolous or non-lichenized fungi. The following validly described taxa remain as autonomous genera or species of foliicolous lichens: Amazonomyces Bat., a generic name taken up for two species previously placed in Stirtonia and Cryptothecia, with two new combinations: Amazonomyces sprucei (R. Sant.) Lücking, Sérus. & Thor comb. nov. [Bas.: Stirtonia sprucei R. Sant.; Syn.: Amazonomyces palmae Bat. & Cavalc], and Amazonomyces farkasiae (Lücking) Lücking, Sérus. & Thor comb. nov. [Bas.: Cryptothecia farkasiae Lücking]; Lyromma Bat. & H. Maia, a distinctive genus of the Dothideales, with two species described by Batista and co-workers, and one new combination: Lyromma palmae (Cavalc. & A. A. Silva) Lücking & Sérus. comb. nov. [Bas.: Anconomyces palmae Cavalc. & A. A. Silva]; Arthonia lecythidicola (Bat. & H. Maia) Lücking & Sérus. comb. nov. [Bas.: Ameropeltomyces lecythidicola Bat. & H. Maia]; Arthonia orbignyae (H. B. P. Upadhyay) Matzer [Bas.: Opegrapha orbignyae H. B. P. Upadhyay; Syn.: Arthonia opegraphina Lücking]; Asterothyrium aspidospermatis (Peres) Lücking & Sérus. comb, nov. [Bas.: Actinoteichus aspidospermatis Peres] and Asterothyrium pernambucense (Cavalc.) Lücking & Sérus. comb. nov. [Bas.: Actinoteichus pernambucensis Cavalc], two apomictic pycnidial forms of Asterothyrium, in addition to the reinstalled A. umbilicatum (Müll. Arg.) Müll. Arg.; Byssoloma guttiferae (Bat. & Peres) Lücking & Sérus. comb. nov. [Bas.: Crocicreomyces guttiferae Bat. & Peres; Syn.: Byssoloma aeruginascens Vězda]; Phyllobathelium leguminosae (Cavalc. & A. A. Silva) Lücking & Sérus. comb. nov. [Bas.: Septoriomyces leguminosae Cavalc. & A. A. Silva]; Tricharia couepiae (Bat.) Lücking & Sérus. comb. nov. [Bas.: Aderkomyces couepiae Bat.] and Trichothelium brasiliense J. L. Bezerra & L. Xavier. Echinoplaca amapensis Bat. & Poroca, a distinctive species with characters that suggest a placement into the Arthoniaceae, will most probably require a new genus when more material is available. One species is validated and two are described as new: Bapalmuia verrucosa Serus. & Lucking spec, nov., Enterographa batistae Lucking & Serus. spec, nov. and Opegrapha ducket Bat., J. L. Bezerra & Cavalc. ex Lucking & Serus.

A revision of several specimens of Catillaria mediterranea Hafellner revealed that two species can be recognized: C. mediterranea s. str., which has 8–16 spores per ascus, grows on foliose and fruticose lichens, and has a Mediterranean- Macaronesian, montane distribution, and C. praedicta Tretiach & Hafellner sp. nov., which has (16-) 24–32 (-48) spores per ascus, occurs on shrubs in coastal Mediterranean maquis, and has a Mediterranean, maritime distribution. The systematic affinities of the two species with the 8-spored C. nigrodavata (Nyl.) Schuler are briefly discussed.

The species of Arthonia s. lat. (Arthoniales, Ascomycotina) lichenicolous on species of Pseudocyphellaria and other Lobariaceae are revised. Thirteen species are accepted, and eight species are described as new (all from the Southern Hemisphere): Arthonia badia Wedin & Hafeliner, A. coriifoliae Wedin & Hafeilner, A. fiavicantis Wedin & Hafellner, A. maculiformis Wedin & Hafeliner, A. minuta Wedin & Hateliner, A. santessoniana Wedin & Hafellner, ‘A.’ semi-immersa Wedin & Hafeilner, and A. subaggregata Wedin & Hafellner. Comparative notes on additional accepted species previously described from Pseudocyphellaria or other Lobariaceae (A. pelvetii, A. plectocarpozdes, A. pseudocyphellariae, A. stzctaria, and A. subconveniens) are included, and a key to the Arthonia (and similar) species growing on Lobariaceae is presented. The coelomycete genus Subhysteropycnis Wedin & Hafellner is described for the species S. maculiformans Wedin & Hafellner, the macroconidal anamorph of Arthonia badia. The lecanoralean genus Corticiruptor Wedin & Hafeliner is described as new to accommodate the single lichenicolous species C. abeloneae (P. M. Jørg.) Wedin & Hafellner comb. nov., and the additional new combination Plectocarpon linitae (R. Sant.) Wedin & Hafellner is proposed. The names Celidium pelvetii Hepp, Sticta aurata b abortiva Schaer. and Arthonia stictarza Nyl. are lectotypified, and the typifications are discussed.

Morphological, anatomical, chemical and ecological evidence show that the South African lichen Roccellina capensis (Nyl. ex Stizenb.) Tehler has developed a dispersal strategy with either sexually dispersed individuals, or vegetatively dispersed, sorediate individuals, hence a putative species-pair. The concept ‘species-pair’ is well-known and widely used in lichenology. It refers to closely related, morphologically indistinguishable lichens that differ from each other by their dispersal strategies only. The so-called ‘ primary species ’ produces fruiting bodies and sexual spores, while its counterpart, the ‘ secondary species ’ is vegetatively dispersed by soredia, isidia or fragmentation. Our study uses molecular information to investigate if R. capensis should be treated as a species-pair or not. The internal transcribed spacer (ITS) of the nuclear ribosomal DNA was sequenced for 17 specimens of R. capensis in order to test if sexual and asexual (sorediate) specimens would group into two distinct, monophyletic groups. Such grouping would support their recognition as separate taxa in a species-pair. We also investigated whether the randomly amplified polymorphic DNA (RAPD) method would be a suitable procedure in population studies of lichens. The analysis of the ITS region produced a single most parsimonious tree. The sexual and asexual specimens were grouped according to their geographical distribution, rather than according to their dispersal strategy. This result clearly shows that the sexual and asexual specimens ofR. capensis do not represent a species-pair. The RAPD data set produced an almost completely unresolved tree due to several homoplasious characters, possibly a result of algal contamination.

Immersaria olivacea, its lichenicolous fungus Polycoccum decolorans, and Immersaria mehadiana are described as new species from Spain and Romania, respectively. A new combination, Immersaria cupreoatra is proposed, and a revised concept of the genera Bellemerea and Immersaria is supplied.

The new species, Polysponna terricola Kantvilas from south-eastern Tasmania, is described and compared to other species in the genus. It is well characterized by a range of morphological, anatomical and ecological characters, especially by the presence of oil paraphyses and oil droplets in the hymenium, features unknown in other members of the genus. Species of Polysporina are best separated by the following characters: size and morphology of the apothecia, size of ascospores, thickness of paraphyses and height of the hymenium. The combinations P. ferniginea (Lettau) M. Steiner and P. pusilla (Anzi) M. Steiner are validated. A key to the taxa studied is provided.