Labyrintha Malcolm, Elix & Owe-Larsson, a new genus in the Porpidiaceae, is described. It is based on the crustose taxon L. implexa Malcolm, Elix & Owe-Larsson, a saxicolous species from acidic rocks in alpine and subalpine areas in New Zealand. Labyrintha is distinguished from closely related genera by a combination of characters: cephalodia, immersed apothecia, large, simple ascospores (60–70 × 30–35 μm), halonate when young and dark-pigmented when mature, fusiform conidia, no cortex, no thallus chemistry, densely packed anticlinal hyphae, and a previously undescribed thallus anatomy in which the photobiont is arranged in anastomosing vertical sheets.

Lecanora pseudogangaleoides spec. nov. is a saxicolous lichen in southeastern Australia. It fits anatomically into the L. subfusca group (=Lecanora s.str.), but differs from most previous concepts of that group in containing usnic acid in addition to atranorin. The presence of usnic acid is now considered to be of less importance in that group, and species containing usnic acid may well belong to Lecanora s.str. Within L. pseudogangaleoides chemical variation with respect to the presence of xanthones was observed and two subspecies are distinguished. Lecanora pseudogangaleoides s.str. lacks xanthones, whereas L. pseudogangaleoides subsp. verdonii subsp. nov. contains the arthothelin chemosyndrome in addition to the normal occurrence of the psoromic acid chemosyndrome. A key orthe distinction of L. pseudogangaleoides and similar species is included.

Micarea confuse, a species easily confused with M. denigrate, is described from heavy-metal contaminated ground in Belgium and The Netherlands. Additional information is provided on the main locality at Budel-Dorplein.

Clathroporina Müll. Arg. (1882), a genus of muriform-spored, pyrenocarpous lichens, is considered to be synonymous with Porina Müll. Arg. nom. cons. (1883). In order to avoid nomenclatural chaos, a proposal should be made to add it to the list of rejected names for Porina. Meanwhile, the following species are recognized: C. biroi Szatala, C. eminentior (NyL) Müll. Arg., C. exocha (Nyl.) Müll. Arg. and C. nuculastrum Müll. Arg. The following new combinations are effected: Aspidothelium cuyabense (Malme) P. M. McCarthy (Thelenella cuyabensis Malme), C. eminentior f. sorediifera (Müll. Arg.) P. M. McCarthy (C. desquamans f. sorediifera Müll. Arg), Laurera straminea (Malme) P. M. McCarthy (T. straminea Malme) and P. tahitensis (Räsänen) P. M. McCarthy (T. tahitensis Räsänen). The name P. farinose Knight is available for C. farinose (Knight) Müll. Arg. and P. grandispora sp. nov. is described from SE China. Fifteen species of Clathroporina and Thelenella sect. Clathroporina are referred to genera outside the Trichotheliaceae.

Phlyctis argena is lichenized with Dictyochloropsis splendida and not with D. reticulata, as thought formerly. This results from in-situ investigation of over 150 lichen thalli and more than 70 cultures of the phycobiont. Material studied from a wide range of geographical locations indicates that specificity of the association in this case is highly probable. Compared to the free–living state, the alga as a lichen partner undergoes distinct changes. Differentiation of strains of D. splendida with respect to morphology and development was not observed.

The new genus Tania Egea, Torrente & Sipman (Arthoniales) with T. lanosa as type species is described from Malaysia. Sagenidiopsis formerly treated as a genus of incertae sedis is included in the order Arthoniales, and the new combination Sagenidiopsis undulatum (Fée) Egea, Tehler, Torrente & Sipman is made. A key to the genera with byssoid thalli in the order Arthoniales is given.

Cyanopyrenia japonica Harada, gen. et sp. nov. is described. It is characterized by having a coccoid cyanobiont, perithecia, sparsely branched paraphyses, thin-walled bitunicate asci, and simple hyaline spores. It resembles Verrucaria, Pyrenocollema, and some Lichinaceae in certain morphological respects, but has no clear affinities. It is known only from the type locality in Shikoku, southwestern Japan, where it grows on frequently submerged rocks in the main flow of a river.

Bacidia caesiovirens S. Ekman & Holien sp. nov. is described from Norway, and the British Isles. It occurs on trunks of deciduous trees in coastal forests. This species is usually sterile and is characterized by its conspicuously blue-green, granular thallus, which contains a bluish, N+ purple pigment. It is closely related to B. biatorina (Körb.) Vain., but differs from this species in a number of features apart from thallus pigmentation: the thallus granules are smaller, the amount of hyphal projections from the surface of the thallus granules is larger, and the internal pigmentation of the apothecia is different. Bacidia auerswaldii (Hepp ex Stizenb.) Mig. has a similarly granular thallus but differs from B. biatorina and B. caesiovirens in having wide, fusiform spores and smaller thallus granules. Bacidia absistens (Nyl.) Arnold has an internal apothecium pigmentation similar to B. caesiovirens, but differs in having a smooth thallus, and an abundance of minute crystals in the excipulum.

The morphology, anatomy, chemistry, habitat and distribution of eight southern-Huropean sorediate, blastidiate or isidiate species of the genus Rinodina are treated. One species, R. nimisii, from Corsica and Sardinia, is new to science. Rinodina erysiphaea, R. sorediata and R. sipmanii are synonyms of R. colobinoides. A key is provided. Other known sorediate, blastidiate or isidiate species arc briefly discussed.

The distribution of many Arctic lichens is well known but their place and time of origin is still conjectural. Land bridges are often suggested but continental drift suggests a possible tie to Gondwanaland and Pangaea. This review suggests consideration of the available evidence for such ideas and emphasizes the need for more exact data from molecular studies of living and amber materials to determine the antiquity of the lichen species involved.

Vegetative diaspores of Lobaria pulmonaria were transplanted to previously uncolonized trees. The early development of the corticated but otherwise non-stratified isidioid soredia was studied mainly by low-temperature scanning electron microscopy. Anchoring hyphae developed from cortical hyphae after 2–4 months and later apical or lateral pseudomeristematic growth zones were formed. After 15 months the growth zones further differentiated into 0·5-mm-broad lobes and revealed a stratified thallus typical for this foliose epiphytic lichen species. The experiment showed that the small population size of L. pulmonaria was limited by the low reproductive potential of the species and that it might fail to compensate for a relatively high disturbance, natural or anthropogenic, in the stand.

The monotypic lichen genera Aphanopsis and Steinia have various ecological and anatomical features in common. Both genera exhibit a particular ascus type and are recognized as representing a family of their own, the Aphanopsidaceae. This family is preliminarily placed in the order Lecanorales.

The northern and southern polar regions differ substantially in topography, climate, terrestrial habitats and in their biota. The Arctic flora comprises around 900 flowering plants, 600–700 bryophytes and 2000 lichens. The Antarctic flora is depauperate by comparison with only two flowering plants, 100–120 bryophytes, and probably only around 200 lichens. Despite considerable taxonomic uncertainty, broad phytogeographic patterns can be outlined, with species having a Maritime Antarctic, Peninsula and Lesser Antarctic, Circum-Antarctic, and Disjunct distribution pattern. The extent of endemism in the flora is unclear. The origin of the Antarctic lichen flora appears ancient in pan, although there is ample evidence for post-Pleistocene or Holocene colonization and invasion.

Descriptions and a key for identification of lichenicolous Arthonia species with red to purple pigments reacting with K are provided. The previously reported species, A. cryptotheciae and A. mazosiicola (as A. mazosiae), are here validly described, and A. haematostigma, A. tavaresii and A. destruens var. nana are new to science. The genus Helicobolomyces is introduced with the type species H. lichenicola, being based on the anamorph of A. cinnabarinula.

Dirina mexicana Tehler from the western coasts of Mexico is proposed as a new species. It mostly resembles D. immersa and D. insulana from the western mediterranean region in Europe.

The medullary structure of 24 Umbilicariaceae species was studied by light microscopy. The objective was to investigate the variability of the medulla of these lichens and to assess the possible implications for thallus ecophysiology and the taxonomic relevance of the anatomy of this layer. Several methods of embedding, sectioning and staining together with the comparison of radial with transverse sections showed important differences in the degree of cohesion of hyphae and their spatial orientation within the medulla. Other important characteristics were the existence of more than one structurally homogeneous layer within the medulla, the frequency of hyphal branching, the relative thickness of the cell wall and lumen and the abundance of gelatinous matter in the intercellular spaces. The medullae studied were grouped into seven main types. The constancy of the types of medulla for certain groups of species makes it a useful secondary character to be considered in the taxonomy of the Umbilicariaceae. The important role of the structure of the medulla in the water relations of the Umbilicariaceae is discussed and a general relationship between medulla type and hydration strategy is suggested

Examination of specimens of Peltigera didactyla, from Africa, Asia, Europe and North America revealed that this sorediate species includes three entities that can be separated on morphological characters. A new species, P. lambinonii, is described from East Africa, and a new combination P. didactyla var. extenuata, is proposed to accommodate morphs from mesic forest habitats in Asia, Europe and North America. Despite this taxonomic reduction, P. didactyla var. didactyla remains a ubiquitous taxon. The former two taxa often produce methyl gyrophorate, which can co-occur with traces of gyrophoric acid. These tridepsides were only rarely detected in var. didactyla; their occasional presence seems to be best explained by hybridization. The taxonomic and ecological significance of these substances is discussed.

The climate, geology and vegetation of Tasmania's South West wilderness are described briefly, with particular reference to lichens. One hundred and sixty-two lichens are recorded from alpine altitudes in the region and the major habitats for alpine lichens are discussed. The flora differs significantly from that of other Tasmanian mountain systems, and this is attributed in part to geology and macroclimate. The region is rich in Tasmanian endemics and distinctly austral species with restricted geographical distributions.