Heavy metal uptake by lichens is briefly reviewed in terms of the trapping of paniculate material and the uptake of soluble cations. The kinetics of uptake to extracellular sites and intracellular carrier-mediated incorporation into cells are compared and the effects of competing cations and the energetics of the processes considered. The influence of heavy metals on lichen growth, morphology and physiology are reviewed emphasizing recent reports showing the greater sensitivity of cyanobacterial compared with chlorophycean lichens, the induction of heavy metal tolerance in the field and laboratory in Peltigera species, and alterations in intracellular cadmium uptake kinetics by some, but not all, tolerant Peltigera populations.

Two national monitoring surveys were carried out within 5 years, using Parmelia sulcata as a biomonitor of trace-element air pollution. The method of sampling was standardized. The lichen samples were analysed by neutron activation analysis. Local variations in element concentrations in lichens from various deciduous tree species from several sampling sites were established. The geographical concentration patterns obtained from the lichen data sets agreed with the element concentration gradients obtained from one dispersion model and measured data of atmospheric concentrations and deposition. Comparison of the two lichen data sets showed the relationship of the geographical concentration patterns with time. Combination of the available data gave insight into the possibility of localization of pollution sources.

In contrast to green algal lichens, cyanobacterial species of different families, growth forms and habitats proved to be unable to attain positive net CO2 assimilation when the dry thalli were treated with air of high relative humidity; they needed liquid water for the reactivation of their photosynthetic apparatus. Identical behaviour is shown by all of the 47 lichen species with cyanobacterial photobionts, from six different genera, studied so far. This suggests a widely distributed, if not general, characteristic of cyanobacterial lichens. The difference in performance between both groups of photobionts was maintained when the lichen thallus was macerated. Furthermore, cultures of Chroococcidiopsis were unable to make use of water vapour hydration for positive net photosynthesis, and were similar in this respect to some free-living aerophilic cyanobacteria tested earlier. Possible physiological implications as well as ecological consequences for water-relation-dependent habitat selection of green-algal and cyanobacterial lichens are discussed.

A revisionary synopsis is presented for the family Trypetheliaceae, based on a separately published phylogenetic analysis of a large number of species, morpho-anatomical and chemical study of extensive material, and revision of numerous type specimens. A total of 418 species is formally accepted in this synopsis, distributed among 15 genera as follows: Aptrootia (3), Architrypethelium (7), Astrothelium (242), Bathelium (16), Bogoriella (29), Constrictolumina (9), Dictyomeridium (7), Distothelia (3), Marcelaria (3), Nigrovothelium (2), Novomicrothelia (1), Polymeridium (50), Pseudopyrenula (20), Trypethelium (16), and Viridothelium (10). All accepted genera, including new genera described separately in this issue, are keyed out and briefly described and discussed, and keys are provided for all accepted species within each genus. Entries with full synonymy and brief descriptions, and in part also discussions, are provided for all accepted species, except those newly described elsewhere in this issue, which are cross-referenced in the corresponding keys. The description of the newly defined genera takes into account phylogeny in combination with morpho-anatomical features with the result that they are mostly recognizable by a combination of thallus, ascoma and ascospore features. Most species previously assigned to the genera Astrothelium, Campylothelium, Cryptothelium, and Trypethelium, based on a schematic concept of ascoma morphology and ascospore septation, are now included in a single genus, Astrothelium, with highly variable ascoma morphology and ascospore septation but invariably with astrothelioid ascospores (at least when young), that is diamond-shaped lumina, and a well-developed, corticate, usually olive-green thallus that often covers the ascomata. While the genera Aptrootia (large, brown, muriform ascospores), Architrypethelium (large, mostly 3-septate ascospores), and Pseudopyrenula (ecorticate, white thalli and astrothelioid ascospores) are maintained, Trypethelium is redefined to include species with raised, pseudostromatic ascomata and multiseptate ascospores with thin septa. The sister group of Trypethelium is the genus Marcelaria, with brightly coloured pseudostromata and muriform ascospores. Bathelium is now limited to species with strongly raised, fully exposed pseudostromata and septate to muriform ascospores with thin septa. Several genera are recognized for more basal lineages with mostly ecorticate, white thalli and solitary, exposed ascomata previously assigned to Arthopyrenia, Mycomicrothelia and Polymeridium, viz. Bogoriella, Constrictolumina, Dictyomeridium, and Novomicrothelia. In addition, separate genera are accepted for the Trypethelium tropicum (Nigrovothelium) and T. virens (Viridothelium) groups. In addition, a refined species concept resulting from phylogenetic studies is employed which pays particular attention to morphological features of the thallus and ascomata. Of a total of 526 names checked, 107 remain synonyms of accepted names and a further eight are newly excluded from the family. Based on these redispositions, the following 146 new combinations are proposed, including reinstatement of numerous names previously subsumed into synonymy: Architrypethelium columbianum (Nyl.) Aptroot & Lücking comb. nov., A. grande (Kremp.) Aptroot & Lücking comb. nov., Astrothelium aeneum (Eschw.) Aptroot & Lücking comb. nov., A. alboverrucum (Makhija & Patw.) Aptroot & Lücking comb. nov., A. amazonum (R. C. Harris) Aptroot & Lücking comb. nov., A. ambiguum (Malme) Aptroot & Lücking comb. nov., A. andamanicum (Makhija & Patw.) Aptroot comb. nov., A. annulare (Spreng.) Aptroot & Lücking comb. nov., A. aurantiacum (Makhija & Patw) Aptroot & Lücking comb. nov., A. auratum (R. C. Harris) Aptroot & Lücking comb. nov., A. aureomaculatum (Vain.) Aptroot & Lücking comb. nov., A. basilicum (Kremp.) Aptroot & Lücking comb. nov., A. bicolor (Taylor) Aptroot & Lücking comb. nov., A. buckii (R. C. Harris) Aptroot & Lücking comb. nov., A. calosporum (Müll. Arg.) Aptroot & Lücking comb. nov., A. cartilagineum (Fée) Aptroot & Lücking comb. nov., A. cecidiogenum (Aptroot & Lücking) Aptroot & Lücking comb. nov., A. ceratinum (Fée) Aptroot & Lücking comb. nov., A. chapadense (Malme) Aptroot & Lücking comb. nov., A. chrysoglyphum (Vain.) Aptroot & Lücking comb. nov., A. chrysostomum (Vain.) Aptroot & Lücking comb. nov., A. cinereorosellum (Kremp.) Aptroot & Lücking comb. nov., A. cinereum (Müll. Arg.) Aptroot & Lücking comb. et stat. nov., A. confluens (Müll. Arg.) Aptroot & Lücking comb. nov., A. consimile (Müll. Arg.) Aptroot & Lücking comb. nov., A. deforme (Fée) Aptroot & Lücking comb. nov., A. defossum (Müll. Arg.) Aptroot & Lücking comb. nov., A. degenerans (Vain.) Aptroot & Lücking comb. nov., A. dissimilum (Makhija & Patw.) Aptroot & Lücking comb. nov., A. effusum (Aptroot & Sipman) Aptroot & Lücking comb. nov., A. endochryseum (Vain.) Aptroot & Lücking comb. nov., A. exostemmatis (Müll. Arg.) Aptroot & Lücking comb. nov., A. feei (C. F. W. Meissn.) Aptroot & Lücking comb. nov., A. ferrugineum (Müll. Arg.) Aptroot & Lücking comb. nov., A. galligenum (Aptroot) Aptroot & Lücking comb. nov., A. gigantosporum (Müll. Arg.) Aptroot & Lücking comb. nov., A. indicum (Upreti & Ajay Singh) Aptroot & Lücking comb. nov., A. infossum (Nyl.) Aptroot & Lücking comb. nov., A. infuscatulum (Müll. Arg.) Aptroot & Lücking comb. nov., A. irregulare (Müll. Arg.) Aptroot & Lücking comb. nov., A. keralense (Upreti & Ajay Singh) Aptroot & Lücking comb. nov., A. kunzei (Fée) Aptroot & Lücking comb. nov., A. leioplacum (Müll. Arg.) Aptroot & Lücking comb. nov., A. lugescens (Nyl.) Aptroot & Lücking comb. nov., A. luridum (Zahlbr.) Aptroot & Lücking comb. nov., A. macrocarpum (Fée) Aptroot & Lücking comb. nov., A. macrosporum (Makhija & Patw.) Aptroot & Lücking comb. nov., A. marcidum (Fée) Aptroot & Lücking comb. nov., A. megaleium (Kremp.) Aptroot & Lücking comb. nov., A. megalophthalmum (Müll. Arg.) Aptroot & Lücking comb. nov., A. megalostomum (Vain.) Aptroot & Lücking comb. nov., A. megaspermum (Mont.) Aptroot & Lücking comb. nov., A. meiophorum (Nyl.) Aptroot & Lücking comb. nov., A. meristosporoides (P. M. McCarthy & Vongshew.) Aptroot & Lücking comb. nov., A. meristosporum (Mont. & Bosch) Aptroot & Lücking comb. nov., A. neogalbineum (R. C. Harris) Aptroot & Lücking comb. nov., A. nigratum (Müll. Arg.) Aptroot & Lücking comb. et stat. nov., A. nigrorufum (Makhija & Patw.) Aptroot & Lücking comb. nov., A. nitidiusculum (Nyl.) Aptroot & Lücking comb. nov., A. octosporum (Vain.) Aptroot & Lücking comb. nov., A. oligocarpum (Müll. Arg.) Aptroot & Lücking comb. nov., A. olivaceofuscum (Zenker) Aptroot & Lücking comb. nov., A. papillosum (P. M. McCarthy) Aptroot & Lücking comb. nov., A. papulosum (Nyl.) Aptroot & Lücking comb. nov., A. peranceps (Kremp.) Aptroot & Lücking comb. nov., A. phaeothelium (Nyl.) Aptroot & Lücking comb. nov., A. phlyctaenua (Fée) Aptroot & Lücking comb. nov., A. porosum (Ach.) Aptroot & Lücking comb. nov., A. praetervisum (Müll. Arg.) Aptroot & Lücking comb. nov., A. pseudoplatystomum (Makhija & Patw.) Aptroot & Lücking comb. nov., A. pseudovariatum (Upreti & Ajay Singh) Aptroot & Lücking comb. nov., A. puiggarii (Müll. Arg.) Aptroot & Lücking comb. nov., A. pulcherrimum (Fée) Aptroot & Lücking comb. nov., A. pupula (Ach.) Aptroot & Lücking comb. nov., A. purpurascens (Müll. Arg.) Aptroot & Lücking comb. nov., A. pustulatum (Vain.) Aptroot & Lücking comb. nov., A. rufescens (Müll. Arg.) Aptroot & Lücking comb. et stat. nov., A. sanguinarium (Malme) Aptroot & Lücking comb. nov., A. santessonii (Letr.-Gal.) Aptroot & Lücking comb. nov., A. saxicola (Malme) Aptroot & Lücking comb. nov., A. scoria (Fée) Aptroot & Lücking comb. nov., A. scorizum (Müll. Arg.) Aptroot & Lücking comb. nov., A. sierraleonense (C. W. Dodge) Aptroot & Lücking comb. nov., A. sikkimense (Makhija & Patw.) Aptroot & Lücking comb. nov., A. spectabile (Aptroot & Ferraro) Aptroot & Lücking comb. nov., A. sphaerioides (Mont.) Aptroot & Lücking comb. nov., A. stramineum (Malme) Aptroot & Lücking comb. nov., A. straminicolor (Nyl.) Aptroot & Lücking comb. nov., A. subcatervarium (Malme) Aptroot & Lücking comb. nov., A. subdiscretum (Nyl.) Aptroot & Lücking comb. nov., A. subdisjunctum (Müll. Arg.) Aptroot & Lücking comb. nov., A. subdissocians (Nyl. ex Vain.) Aptroot & Lücking comb. et stat. nov., A. superbum (Fr.) Aptroot & Lücking comb. nov., A. tenue (Aptroot) Aptroot & Lücking comb. nov., A. thelotremoides (Nyl.) Aptroot & Lücking comb. nov., A. trypethelizans (Nyl.) Aptroot & Lücking comb. nov., A. tuberculosum (Vain.) Aptroot & Lücking comb. nov., A. ubianense (Vain.) Aptroot & Lücking comb. nov., A. variatum (Nyl.) Aptroot & Lücking comb. nov., A. vezdae (Makhija & Patw.) Aptroot & Lücking comb. nov., Bathelium austroafricanum (Zahlbr.) Aptroot & Lücking comb. nov., B. nigroporum (Makhija & Patw.) Aptroot & Lücking comb. nov., Bogoriella alata (Groenh. ex Aptroot) Aptroot & Lücking comb. nov., B. annonacea (Müll. Arg.) Aptroot & Lücking comb. nov., B. apposita (Nyl.) Aptroot & Lücking comb. nov., B. captiosa (Kremp.) Aptroot & Lücking comb. nov., B. collospora (Vain.) Aptroot & Lücking comb. nov., B. confluens (Müll. Arg.) Aptroot & Lücking comb. nov., B. conothelena (Nyl.) Aptroot & Lücking comb. nov., B. decipiens (Müll. Arg.) Aptroot & Lücking comb. nov., B. exigua (Müll. Arg.) Aptroot & Lücking comb. nov., B. fumosula (Zahlbr.) Aptroot & Lücking comb. nov., B. hemisphaerica (Müll. Arg.) Aptroot & Lücking comb. nov., B. lateralis (Sipman) Aptroot & Lücking comb. nov., B. leuckertii (D. Hawksw. & J. C. David) Aptroot & Lücking comb. nov., B. macrocarpa (Komposch, Aptroot & Hafellner) Aptroot & Lücking comb. nov., B. megaspora (Aptroot & M. Cáceres) Aptroot & Lücking comb. nov., B. miculiformis (Nyl. ex Müll. Arg.) Aptroot & Lücking comb. nov., B. minutula (Zahlbr.) Aptroot & Lücking comb. nov., B. modesta (Müll. Arg.) Aptroot & Lücking comb. nov., B. nonensis (Stirt.) Aptroot & Lücking comb. nov., B. obovata (Stirt.) Aptroot & Lücking comb. nov., B. pachytheca (Sacc. & Syd.) Aptroot & Lücking comb. nov., B. punctata (Aptroot) Aptroot & Lücking comb. nov., B. queenslandica (Müll. Arg.) Aptroot & Lücking comb. nov., B. socialis (Zahlbr.) Aptroot & Lücking comb. nov., B. striguloides (Sérus. & Aptroot) Aptroot & Lücking comb. nov., B. subfallens (Müll. Arg.) Aptroot & Lücking comb. nov., B. thelena (Ach.) Aptroot & Lücking comb. nov., B. triangularis (Aptroot) Aptroot & Lücking comb. nov., B. xanthonica (Komposch, Aptroot & Hafellner) Aptroot & Lücking comb. nov., Constrictolumina esenbeckiana (Fée) Lücking, M. P. Nelsen & Aptroot comb. nov., C. leucostoma (Müll. Arg.) Lücking, M. P. Nelsen & Aptroot comb. nov., C. lyrata (R. C. Harris) Lücking, M. P. Nelsen & Aptroot comb. nov., C. majuscula (Nyl.) Lücking, M. P. Nelsen & Aptroot comb. nov., C. malaccitula (Nyl.) Lücking, M. P. Nelsen & Aptroot comb. nov., C. porospora (Vain.) Lücking, M. P. Nelsen & Aptroot comb. nov., Dictyomeridium amylosporum (Vain.) Aptroot, M. P. Nelsen & Lücking comb. nov., D. campylothelioides (Aptroot & Sipman) Aptroot, M. P. Nelsen & Lücking comb. nov., D. immersum (Aptroot, A. A. Menezes & M. Cáceres) Aptroot, M. P. Nelsen & Lücking comb. nov., D. isohypocrellinum (Xavier-Leite, M. Cáceres & Aptroot) Aptroot, M. P. Nelsen & Lücking comb. nov., D. paraproponens (Aptroot, M. Cáceres & E. L. Lima) Aptroot, M. P. Nelsen & Lücking comb. nov., Distothelia rubrostoma (Aptroot) Aptroot & Lücking comb. nov., Phyllobathelium chlorogastricum (Müll. Arg.) Aptroot & Lücking comb. nov., Pseudopyrenula cubana (Müll. Arg.) Aptroot & Lücking comb. nov., Viridothelium cinereoglaucescens (Vain.) Lücking, M. P. Nelsen & Aptroot comb. nov., V. indutum (Stirt.) Aptroot & Lücking comb. nov., and V. megaspermum (Makhija & Patw.) Aptroot & Lücking comb. nov. In addition, six replacement names are proposed: Astrothelium campylocartilagineum Aptroot & Lücking nom. nov., A. grossoides Aptroot & Lücking nom. nov., A. octosporoides Aptroot & Lücking nom. nov., A. scoriothelium Aptroot & Lücking nom. nov., A. pyrenastrosulphureum Aptroot & Lücking nom. nov., and Bathelium pruinolucens Aptroot & Lücking nom. et stat. nov. Along with this, 57 lectotypes are newly designated. Most species (392 out of 418) are illustrated, with a total of 697 images in 59 plates, including 406 type specimens. Where appropriate, taxa are briefly discussed. New country or continental records are listed for many species in their revised circumscription. A checklist of taxa described or placed in genera belonging in Trypetheliaceae but previously excluded from the family, and their current names, is also provided.

A total of 69 species of lichens have been collected from various locations around New Zealand. Screening of extracts of these species for antimicrobial, antiviral and cytotoxic activity showed a high proportion with biological activity. Active extracts were generally from species known to contain phenolic compounds. Bioactivity-directed isolation work on Cladia retipora, Pseudocyphellaria glabra and P. homoeophylla led to the identification of usnic acid as the main antimicrobial, cytotoxic and antiviral component in these three species.

Cytological aspects of the mycobiont-phycobiont contact were investigated in the lichen species Peltigera aphthosa, Cladonia macrophylla, Cladonia caespiticia and Parmelia tiliacea by means of freeze-etch and thin sectioning techniques, and by replication of isolated fragments of myco- and phycobiont cell walls.

In the symbiotic state of the mycobionts investigated a thin outermost wall layer with a distinct pattern was observed mainly in the hyphae contacting phycobiont cells and in the upper medullary layer. No comparable structures were noted on the hyphal surface of the cultured mycobionts of the Cladonia and Parmelia species investigated. A distinct rodlet layer was found on the hyphal surface of the mycobiont of Peltigera aphthosa, while mycobionts of Cladonia macrophylla, C. caespiticia and Parmelia tiliacea had a mosaic of small, irregular ridges, each corresponding in its size to a bundle of rodlets on the outermost wall layer. Comparable surface layers have been described in aerial hyphae of a great number of non-lichenized fungi.

The rodlet layer of the mycobiont wall surface of Peltigera aphthosa adheres tightly to the outermost layer of the sporopollenin-containing cell wall of the Coccomyxa phycobiont. Mature trebouxioid phycobiont cells of the Cladonia and Parmelia species investigated in the symbiotic state had an outermost wall layer which was structurally indistinguishable from the tessellated surface layer of the mycobiont cells. A rodlet pattern was detected in the outermost wall layer of Trebouxia autospores still surrounded by the cellulosic mother cell wall. In mature Trebouxia cells the bundles of rodlets became increasingly covered by a homogeneous material, and thus attained the same tessellated pattern which was observed on the mycobiont wall surface. No comparable structures were found on the wall surface after culturing the Trebouxia phycobionts axenically in liquid media. Confluence of the tessellated surface layers of fungal and algal origin was noted at the contact sites of growing hyphal tips and young Trebouxia cells.

The possible correlations between these cytological features and published immunological data on the cell surface of cultured and symbiotic lichen myco- and phycobionts are discussed.

The importance of mineralogy in determining lichen assemblages occurring on metalliferous rocks and derived soils is discussed with reference to environments enriched in metals from mine and smelter wastes and other sites involving human activities. A study of lichens growing on Cu and Fe sulphide-rich rocks in Scandinavia is presented. This data suggests that the composition of the lichen communities is governed by mineralogy, which influences the mobility and availability of Cu2+ and Fe2+ in the environment, rather than the total concentrations of either metals within the substratum. A new lichen community, the Lecideion inopis Purvis, is described characterized by the faithful species Lecidea inops, Psilolechia leprosa and several Cu-rich ecotypes. This community occurs alkaline environments where Cu is fixed predominantly as a secondary hydroxide or carbonate. Conversely, low pH, Fe sulphide-rich environments, where Cu may also be present, are characterized by the Acarosporion sinopicae, which includes several species with a rusty colouration. Contrasting assemblages rich in terricolous ephemeral species, especially Vezdaea spp. occurring in Pb/Zn-rich environments, and the comparatively species-poor assemblages on Cr and Ni-rich ultrabasic rocks, are also reviewed. Although mine spoil heaps and other mineralized environments are perceived in human terms as toxic, they may support a diversity of lichens, including rare taxa restricted to these sites. The systematic description of these lichen communities in relation to rock mineralogy and chemical processes are necessary if physiological tolerance and speciation are to be understood.

The edge effect of large clear-cuts on the epiphytic lichen flora of Picea abies in old-growth forest fragments was studied at three south-exposed and four north-exposed forest clear-cut edges in middle boreal Finland. The sampling of the species cover on trunk bases was carried out along four transects parallel to the forest margin: (1) at the forest margin, (2) 10 m from the margin, (3) 20 m from the margin and (4) 50 m from the margin. In addition, control trees were sampled > 100 m from nearest edge. Our results showed that the epiphytic lichen species diversity was lower at the forest margin than in the forest interior for sunny south-facing edges, while the species diversity in north-exposed edges was independent of the distance from the forest margin. The cover of a common and abundant lichen species, Parmeliopsis ambigua, was slightly higher at the forest edge and decreased inside the forest for both south-exposed and north-exposed edges.

Parmelia barrenoae is described as new to science in the P. sulcata complex on the basis of morphological and molecular data. The new species is superficially similar to P. sulcata but differs in having simple rhizines whereas the other species of the complex have squarrose rhizines. Nuclear ITS rDNA and partial β-tubulin gene sequences have been used as molecular markers. In the phylogenetic analysis, P. sulcata falls into four well supported clades, one of them corresponds to the morphotype that is described here as a new taxon. Six samples of the new taxon from different locations on the Iberian Peninsula form a strongly supported monophyletic group.

Survival strategies of 34 species of lichens from a range of substrata, climates and growth forms were examined using the triangular ordination procedure of Grime. Triangular ordination is apparently an appropriate technique to apply to lichens, all available data falling within a triangle except for two foliicolous species which are probably partial leaf parasites. Statistically significant relationships between survival strategy and growth form, mode of asexual reproduction, substratum preference, family affiliation, and diversity of secondary chemical biosynthetic pathways have been demonstrated.

The distribution of alectorioid lichens in subalpine spruce-fir forests of north-central British Columbia is strongly influenced by vertical position within the canopy; Bryoria dominates upper canopy exposures, while Alectoria dominates lower canopy positions. The hypothesis that this height-related niche partitioning reflects differential growth responses to gradients in canopy microclimate is examined. Field measurements of canopy microclimate, taken over a 2-year period, were used in conjunction with laboratory-based measurements of net photosynthesis (NP) and dark respiration to model net assimilation (NA) response of Alectoria sarmentosa and Bryoria spp. (mixed collections of Bryoria fremontii and B. pseudofuscescens) at two different heights (15 and 4 m) within the canopy. Microclimate measurements indicate that lichen thalli are regularly hydrated from snowmelt events during the winter period (October-April), totalling 26 and 29% of the time, respectively, for Alectoria and Bryoria, though most winter hydration exposure (c. 75%) occurred in the dark. In the summer (May-September), rainfall was the major hydration source, with Alectoria and Bryoria each hydrated c. 16% of the time (45% of this in the dark). The NP temperature optimum (Topt) in light saturated thalli of Alectoria was 18.1 and 22.9°C, for winter and summer measurements, respectively. In Bryoria the corresponding seasonal rise in Topt was smaller, from 15.9 to 16.3°C. Both species showed an increase in maximum rates of NP during the summer period, from 1.52 to 1.92 mg CO2 g−1h−1 for Alectoria, and from 1.79 to 2.33 mg CO2g−1 h−1 for Bryoria. Although lichen hydration events peaked in early winter (October and November), NA modeling predicts that maximum growth should occur during the summer period. In Alectoria, higher rates of NA were predicted for thalli in lower canopy positions, especially during the summer months. In Bryoria, no clear trends of NA uptake with canopy position were observed. Thus, while NP response to gradients of canopy microclimate may provide a basis for niche partitioning in Alectoria, other factors (perhaps exclusionary) may be more important for Bryoria. One such factor is documented, namely the greater sensitivity of Bryoria to extended hydration exposure and we speculate that greater rates of fragmentation in upper canopy exposures may limit upper canopy biomass accumulation in Alectoria. Niche partitioning in these alectorioid lichens may therefore reflect both positive (growth responses) and negative (physical and physiological limitations) responses to gradients in canopy microclimate.

Since the last compilation in 1983, the number of lichenicolous fungi (and lichenicolous lichens) recorded in Great Britain and Ireland has increased from 218 to 403 species (a rise of 85%). The introduction includes accounts of: the history of investigation, circumscription, phylogenetic relationships, symbiotic interactions, dispersal and establishment, distribution, culture, host restriction, and identification. The checklist enumerates the recorded species. Information is provided on the systematic position of each genus, together with the authors and dates of publication of all accepted names; synonyms used in the literature of the two countries since 1910 are cross-indexed. References to pertinent literature with descriptions and discussions are included, together with notes on particular species. The list of references cited includes 298 publications. The following new scientific names are introduced: Diederichia gen. nov., and Dactylospora scapanaria (syn. Lecidea scapanaria), Diederichia pseudevemiae (syn. Macrophomina pseudeverniae), Muellerella ventosicola (syn. Microthelia ventosicola) and Nigromacula uniseptata (syn. Vouauxiella uniseptata) combs, nov.

The factors influencing the predominance of one of the two mineral forms of calcium oxalate (CO), the monohydrated whewellite (COM) and the di-hydrated weddellite (COD), forming the pruina of the upper cortex of lichens, have been investigated through a simple, sensitive histochemical assay: toluidine blue O (TBO), a metachromatic staining test. The differential reactivity of 43 thalli of 17 pruinose foliose species, supplemented by X-ray diffraction analysis and observations with polarizing and scanning electron microscopy, suggests that the histochemical reactivity of hyphal walls and cementing substances of the upper cortex are related to the density of anionic charges. These factors are probably due to the occurrence of polyuronic acid substances that strongly affects the mineralization of CO. Di-hydrated wedellite is always associated with TBO metachromatic reactivity, and COM with orthochromatic reactivity. When the material has an ambiguous ortho/metachromatic reactivity, COD and COM may occur together. This study presents the first experimental evidence that in lichens CO biomineralization is at least partially biologically controlled.

A review of algal (including cyanobacterial) symbionts associated with lichen-forming fungi is presented. General aspects of their biology relevant to lichen symbioses are summarized. The genera of algae currently believed to include lichen symbionts are outlined; approximately 50 can be recognized at present. References reporting algal taxa in lichen symbiosis are tabulated, with emphasis on those published since the 1988 review by Tschermak-Woess, and particularly those providing molecular evidence for their identifications. This review is dedicated in honour of Austrian phycologist Elisabeth Tschermak-Woess (1917–2001), for her numerous and significant contributions to our knowledge of lichen algae (some published under the names Elisabeth Tschermak and Liesl Tschermak).

We have investigated whether DNA extraction protocols designed specifically for fungi and/or lichens perform better on lichens than do corresponding protocols designed for plants and insects. Two different PCR-amplification protocols were used to evaluate the quality of the DNA extracted with each method. The DNA extractions with highest quality were obtained with the protocols designed for insects and plants, and the most successful amplifications were obtained with Ready-To-Go PCR Beads. This indicates that fungal or lichen specific protocols might not be necessary for successful extraction of high quality DNA from lichens.

Lichens are widely acknowledged to be a key component of high latitude ecosystems. However, the time investment needed for full inventories and the lack of taxonomic identification resources for crustose lichen and lichenicolous fungal diversity have hampered efforts to fully gauge the depth of species richness in these ecosystems. Using a combination of classical field inventory and extensive deployment of chemical and molecular analysis, we assessed the diversity of lichens and associated fungi in Glacier Bay National Park, Alaska (USA), a mixed landscape of coastal boreal rainforest and early successional low elevation habitats deglaciated after the Little Ice Age. We collected nearly 5000 specimens and found a total of 947 taxa, including 831 taxa of lichen-forming and 96 taxa of lichenicolous fungi together with 20 taxa of saprotrophic fungi typically included in lichen studies. A total of 98 species (10.3% of those detected) could not be assigned to known species and of those, two genera and 27 species are described here as new to science: Atrophysma cyanomelanos gen. et sp. nov., Bacidina circumpulla, Biatora marmorea, Carneothele sphagnicola gen. et sp. nov., Cirrenalia lichenicola, Corticifraga nephromatis, Fuscidea muskeg, Fuscopannaria dillmaniae, Halecania athallina, Hydropunctaria alaskana, Lambiella aliphatica, Lecania hydrophobica, Lecanora viridipruinosa, Lecidea griseomarginata, L. streveleri, Miriquidica gyrizans, Niesslia peltigerae, Ochrolechia cooperi, Placynthium glaciale, Porpidia seakensis, Rhizocarpon haidense, Sagiolechia phaeospora, Sclerococcum fissurinae, Spilonema maritimum, Thelocarpon immersum, Toensbergia blastidiata and Xenonectriella nephromatis. An additional 71 ‘known unknown’ species are cursorily described. Four new combinations are made: Lepra subvelata (G. K. Merr.) T. Sprib., Ochrolechia minuta (Degel.) T. Sprib., Steineropsis laceratula (Hue) T. Sprib. & Ekman and Toensbergia geminipara (Th. Fr.) T. Sprib. & Resl. Thirty-eight taxa are new to North America and 93 additional taxa new to Alaska. We use four to eight DNA loci to validate the placement of ten of the new species in the orders Baeomycetales, Ostropales, Lecanorales, Peltigerales, Pertusariales and the broader class Lecanoromycetes with maximum likelihood analyses. We present a total of 280 new fungal DNA sequences. The lichen inventory from Glacier Bay National Park represents the second largest number of lichens and associated fungi documented from an area of comparable size and the largest to date in North America. Coming from almost 60°N, these results again underline the potential for high lichen diversity in high latitude ecosystems.

Population genetics investigates the distribution of genetic variation in natural populations and the genetic differentiation among populations. Lichen-forming fungi are exciting subjects for population genetic studies due to their obligate symbiosis with a green-algal and/or cyanobacterial photobiont, and because their different reproductive strategies could influence fungal genetic structures in various ways. In this review, first, I briefly summarize the results from studies of chemotype variation in populations of lichen-forming fungi. Second, I compare and evaluate the DNA-based molecular tools available for population genetics of lichen-forming fungi. Third, I review the literature available on the genetic structure of lichen fungi to show general trends. I discuss some fascinating examples, and point out directions for future research.