John Lightfoot's account of lichens in Flora Scotica was the first Scottish lichen Flora and as such it was novel in several respects: 1) it was published in English; 2) it drew on the knowledge and expertise of several key local collectors and treated lichens from alpine areas for the first time; 3) it made lichens accessible in providing Linnaean binomials, colloquial English, and frequently also Gaelic names, together with lively descriptions, details of ecology, and medicinal or traditional uses when these were known. Of the 117 taxa listed, 109 were classified in the genus Lichen, five in Byssus, two in Mucor and one in Fucus. Nineteen taxa were newly described, of which five are still in current use. John Lightfoot's life, work and botanical friendships are also briefly discussed.

The lichenized basidiomycete known as Dictyonemainterruptum is a widely distributed but rare, oceanic, western European species known from the British Isles, the Pyrenees, the Azores, and Madeira. Unfortunately, the name has never been validly published. The species was first described in the cyanobacterial genus Calothrix in 1833, which predates the starting point of heterocystous bacterial nomenclature, 1 January 1886. The epithet was never subsequently included in a validly published binomial and its combination into Dictyonema was therefore invalid as well. There was also controversy about whether the epithet applied to the cyanobacterial photobiont (as originally intended) or to the lichen fungus (as proposed later). Because of the lack of a valid description for this epithet, we have chosen to establish a new name, Dictyonema coppinsii Lücking, Barrie & Genney, for the lichenized fungus at hand, whereas the cyanobacterial photobiont is validated with the genus name Rhizonema Lücking & Barrie, adopting the epithet interruptum for it, and placed in a separate family, Rhizonemataceae Büdel & Kauff ex Lücking & Barrie.

Porpidia irrigua is described as a new species; it has a white thallus, sessile apothecia, contains the depside methyl 2'-O-methylmicrophyllinate, and grows on damp siliceous rocks. It was previously included in a wide concept of P. contraponenda, but that species differs in the thicker thallus, partly immersed apothecia, and the possession of an unidentified depside in addition to methyl 2′-O-methylmicrophyllinate, which can be separated by thin-layer chromatography using Solvent System G.

The new genus Brianaria S. Ekman & M. Svensson is introduced for the Micarea sylvicola group, with the new combinations Brianaria bauschiana (Körb.) S. Ekman & M. Svensson, B. lutulata (Nyl.) S. Ekman & M. Svensson, B.sylvicola (Flot. ex Körb.) S. Ekman & M. Svensson and B. tuberculata (Sommerf.) S. Ekman & M. Svensson. The new genus is characterized by a chlorococcoid, non-micareoid photobiont, small, convex apothecia without an excipulum, an ascus of the ‘Psora-type’, 0–1-septate ascospores, dimorphic paraphyses, and immersed pycnidia containing bacilliform conidia. Brianaria is shown to form a monophyletic group in the Psoraceae, where it is probably the sister group to Psora and Protoblastenia.

The new species Micarea usneae is described from Madeira. It has been found at two localities where it grew on epiphytic Usnea thalli. Micarea usneae is distinguished by a very thin pale brownish thallus, pallid to greyish black or bluish subglobose apothecia of 0·1–0·3 mm diameter, very narrow (1·5–2·5 µm) ascospores, black pycnidia and strongly curved to sigmoid macroconidia. Phylogenetic analyses using mtSSU sequences place the new species in the Micarea peliocarpa group. Catillaria usneicola and Cladonia parasitica are recorded for the first time from Madeira. A key to the lichenicolous species on Usnea in Macaronesia is provided.

The new species Miriquidica invadens Hafellner, Obermayer & Tretiach is described and reported from Austria, Bulgaria, Italy, Switzerland, France and Spain. From a morphological point of view the species belongs to the M. griseoatra group, in which it is, so far, the only constantly lichenicolous taxon. Chemically it is characterized by the regular presence of miriquidic acid, stictic acid, and constictic acid (in variable amounts). It starts its ontogenetic life cycle as an obligate youth parasite on Sporastatia, usually S. polyspora.

Morpho-anatomical treatments of other species of the Miriquidica griseoatra group occurring in Europe, based on the examination of type material, are also presented. According to the characters exhibited by the lectotype of Lecidea contigua var. griseoatra Flot., M. griseoatra (Flot.) Hertel & Rambold is the correct name for a montane species with subdivided areoles and immersed, laterally adnate apothecia with a pigmented hypothecium. Specimens exhibiting this set of characters were usually named M. obnubila auct. According to the characters observed on the lectotype of Lecidea (Biatora) obnubila Th. Fr. & Hellb., M. obnubila (Th. Fr. & Hellb.) Hertel & Rambold is a species with sessile apothecia with a hyaline hypothecium. Lecidea subplumbea Anzi does not constitute a heterotypic synonym of Lecidea griseoatra (Flot.) Schaer. but is the legitimate name at the species level for Miriquidica griseoatra sensu auct., and therefore M. subplumbea (Anzi) Cl. Roux is the correct name for that taxon. Lecidea inserena Nyl. is confirmed as a heterotypic synonym of Lecidea subplumbea Anzi. Lecidea plumbea Garov. ex A. Massal. is an earlier heterotypic synonym of Miriquidica limitata Hertel & Rambold and, therefore, the new combination M. plumbea (Garov. ex A. Massal.) Hafellner, Obermayer & Tretiach is introduced.

Lectotypes are designated for Lecidea contigua var. griseoatra Flot., Lecidea inserena Nyl., Lecidea obnubila Th. Fr. & Hellb., Lecidea plumbea Garov. ex A. Massal., and Lecidea subplumbea Anzi. A key to the taxa of the M. griseoatra-group and other Miriquidica taxa with a grey thallus is provided.

Two new genera and four new species of bulbil-forming basidiomycetes are described. Phylogenetic analyses of nuLSU and ITS sequences place them in Cantharellales. A facultative lichenicolous species with yellow to orange-yellow bulbils from South America groups with the type of Burgella and is consequently described as B. lutea. The new species and genus Burgellopsis nivea is introduced for material from Scotland with white bulbils overgrowing saxicolous lichens. An obligate lichenicolous species with particularly large, applanate bulbils developing over Peltigerales in South America could not be placed accurately using ITS sequences and is described as the new species and genus Bulbilla applanata. A European species with brown, facultatively lichenicolous bulbils grouped with Ceratobasidium and Thanatephorus species and is described as the new Ceratobasidium bulbillifaciens.

Five new species of Rimularia, all endemic to Tasmania, are described, discussed and illustrated: Four species are saxicolous: R. albotessellata Kantvilas (containing pannarin): R. aspicilioides Kantvilas (containing 2′-O–methylperlatolic acid and with apothecia with a thalline margin); R. circumgrisea Kantvilas (containing norstictic acid, and with ascospores 8·5–14·0×5·0–6·5 µm); and R. coppinsiana Kantvilas (containing bourgeanic acid and with ascospores 10–19×7–12 µm). The corticolous R. asteriphila Kantvilas lacks lichen substances, contains Sedifolia-grey pigment and has ascospores 10–15×7–10 µm. The widespread R. psephota (Tuck.) Hertel & Rambold, with which several of the new taxa are compared, is also described, based on Tasmanian collections. Several chemical compounds, including bourgeanic acid, pannarin and 2′–O–methylperlatolic acid, are recorded for the genus for the first time. A key to the 12 species currently recorded for Tasmania is presented.

The new species Bacidia termitophila, Coenogonium coppinsii, Fellhanera termitophila, and Micarea termitophila are described from termite nests in rainforest in Rondônia and adjacent Amazonas. Lichens were found on termite mounds on the ground but most of the species were also found on termite nests on trees. This substratum may serve as the most important locality for terricolous lichens in rainforests, and the natural habitat for species known mostly from road banks.

Spilonema was originally described to accommodate an unusual group of cyanolichens with thread-like, cushion-forming thalli, and has long been placed in Coccocarpiaceae based on ascomatal development. However, Spilonema is the only genus of Peltigerales to include species lichenized with the cyanobacterial genus Stigonema, and the evolutionary relationships of Spilonema to other genera in the family have yet to be tested using molecular data. We present evidence from combined nuclear 28S, 18S and mitochondrial 12S rDNA to confirm the placement of the core species of Spilonema (S. paradoxum and S. revertens) in Coccocarpiaceae. Our data further show that despite possessing a different genus of photobiont (Scytonema), the north Pacific endemic genus Spilonemella must be included within Spilonema, suggesting that closely related species of the genus have changed photobionts in the course of evolution. However, we recovered Spilonema dendroides, one of the only lichens known to associate with the cyanobacterial genus Hyphomorpha, as only distantly related to the Coccocarpiaceae. The evolutionary relationships of this species are as yet unclear but it may occupy a basal position in the Peltigerales. We create for this species the new genus Erinacellus T. Sprib., Muggia & Tønsberg.

Eight new species of Lecideaceae are described from the southern subpolar region: Bryobilimbia coppinsiana Fryday, a saxicolous species with one septate ascospores (Campbell Island, New Zealand); Immersaria fuliginosa Fryday, with a thallus composed of thalloconidia (Falkland Islands); Lecidea aurantia Fryday, with an orange thallus (Auckland Islands, New Zealand); L. campbellensis Fryday, with an endolithic thallus and apothecia resembling those of a species of Porpidia (Campbell Island); Poeltiaria ochyrae Hertel, which is similar to P. subincongua but with a thick areolate thallus (South Orkney and South Shetland Islands); P. tasmanica Fryday, which is similar to P. urbanskyana but with smaller ascopores (Tasmania); Poeltidea inspersa Fryday with an enolithic thallus and a hymenium with large oil globules (Falkland Islands); and Porpidia vulcanoides Hertel & Fryday with immersed apothecia with a thick margin and large ascospores (SW Chile). Lecidea kalbii Hertel is resurrected from the synonymy of L. mannii Tuck. and treated as a distinct species. The circumscription of genera within the Lecideaceae is also discussed: Poeltiaria is shown to be heterogeneous, and the genera Labyrintha and Notolecidea are reduced to synonymy with Poeltidea and Poeltiaria respectively, and the new combinations Poeltidia implexa (Malcolm et al.) Hertel & Fryday and Poeltiaria subcontinua (Hertel) Hertel & Fryday made. A key to the genera of Lecideaceae s. lat. is provided.

Detailed anatomical and chemical studies conducted on recent collections made in almost all suitable habitats on Réunion, a small remote tropical island in the Indian Ocean, yielded a surprising diversity in the widespread lichen genus Micarea (Pilocarpaceae, Lecanorales). Twenty-one species are recognized, including 13 described here as new to science. They are: Micarea alectorialica, M. bebourensis, M. borbonica, M. boryana, M. cilaoensis, M. hyalinoxanthonica, M. isidiosa, M. melanoprasina, M. pseudocoppinsii, M. pseudolignaria, M. sublithinella, M. takamakae and M. tenuispora. Notes on local ecology and important biogeographical features are also given and a key to the species is provided. Isidiiform areolae are reported for the first time in the genus (M. isidiosa and M. tenuispora), as well as the production of protolichesterinic and confluentic acids (M. sublithinella and M. takamakae, respectively). Two groups within the genus are species-rich on the island: the M. peliocarpa group with possibly 5 species, including 3 new to science, and the M. prasina group with 4 species, including 2 new to science. Micarea levicula is reported here for the first time since its description, and the status of the material that can be referred to M. micrococca s. lat. needs further study.

The lichen genus Biatora comprises inconspicuous crustose lichens that are typically found on organic substrata such as tree bark, bryophytes and detritus. During the last 20 years many new species have been added to the genus making its delimitation more and more difficult. The infrageneric relationships of the 42 species have never been investigated thoroughly. Using DNA sequences from three gene loci (ITS, RPB2, mrSSU) and 59 OTUs, an attempt was made to reconstruct the phylogenetic relationships of Biatora and its infrageneric groups. Cliostomum appears to be the closest relative of Biatora. The position of Mycobilimbia in the Lecania-clade is confirmed. Phylogenetic relationships within Biatora are poorly supported, but six different species groups that are also phenotypically distinguished are more or less well supported: the vernalis-, meiocarpa-, hertelii-, ocelliformis-, beckhausii- and rufidula- groups. The analysis also confirms the presence of several undescribed taxa. Biatora subduplex as currently circumscribed appears to be heterogeneous, as does B. helvola. Based on the phylogeny, the distributional range of B. alaskana is extended to Japan. The new combinations Biatora ementiens (Nyl.) Printzen and Biatora hemipolia (Nyl.) S. Ekman & Printzen are made and both names are typified.

Coarse deadwood provides an important habitat for a suite of niche-specialist lichens in old-growth forests, for example, snags (standing dead trees) and fallen logs. Conversely, the scarcity of deadwood in managed forests is a limiting factor to lichen diversity, though cut stumps may provide an alternative habitat for deadwood species. The surface of cut stumps is an ecologically useful study system, facilitating standardized sampling with which to determine the pattern and process of deadwood succession. This study examined vegetation patterns for the surface of cut stumps at Abernethy RSPB Reserve in northern Scotland. We demonstrate the interrelationship between key topographic, management and edaphic factors during a successional process of terrestrialization. Consequently, we recommend that deadwood diversity might be maximized by 1) creating managed plots with varying degrees of canopy openness for sites with different levels of topographic exposure, and 2) providing cut stumps at different heights within plots, to ensure that during a rotational period the process of terrestrialization operates at different speeds among individual microhabitats. The study examined successional processes on cut stumps using two recently accessible and powerful statistical methods: 1) nonparametric multiplicative regression (NPMR), and 2) multivariate regression trees (MRT). The principles on which these techniques are based are becoming the preferred statistical framework with which to provide robust interpretation of field-sampled data; they are unconstrained by prior assumptions as to the form of a species' niche response, and are data-led models evaluated based on cross-validated performance, thereby avoiding the complication of multiple hypothesis tests.

The criteria set out by the International Union for Conservation of Nature to identify threatened species requires information on population trends which, for priority lichen species within Scotland, is lacking. Collecting such data is problematic as there is a lack of empirical information on the performance of different sampling designs and survey methodologies. Using Pseudocyphellaria norvegica as an example species, we tested differences in the efficiency of 3 transect patterns and a 20 minute search for surveying 100×100 m cells of potentially suitable habitat. The methods were not intended to census the total population of the cells but, rather, to provide a standardized, repeatable estimate of the population density to allow detection of trends through time. We also tested the repeatability of the methods between surveyors. The results provided no evidence to suggest that controlled survey methodologies using fixed transect patterns were any better in terms of consistency between surveyors or numbers of occupied trees found than 20 minute searches of the areas within each 100×100 m cell deemed suitable for the target species by an experienced surveyor. Given that following the fixed transect patterns took approximately twice as long as a 20 minute search, the search method would clearly be more cost-effective when there are large numbers of cells to survey. For all survey methods variability between surveyors was high, meaning that it would be extremely difficult to detect temporal changes in populations, and hence identify population trends. We also examined the extent to which recording presence/absence at the 1 ha scale might improve consistency between surveyors and found that it reduced, but did not eliminate, the surveyor variability. Recording only presence/absence would allow greater numbers of cells to be surveyed using the same level of resources, but would reduce the amount of information available per cell for use in analysis of population trends. We conclude that controlling inter-surveyor variability while collecting adequate data for population trend analysis is a major issue when planning and implementing any large-scale survey of lichen species.