The genus Arthopyrenia is redefined to include only corticolous lichenized or non-lichenized fungi. A key and notes are provided for the 14 species accepted for the British Isles, including three new species, A. carneobrunneola, A. ranunculospora and A. viridescens. Arthopyrenia nilescens is resurrected from synonymy, A. cinereopruinosa is confirmed as occurring in the British Isles, and A. fraxini, A. salicis and A. subcerasi are added to the British list. The following names are lectotypined: Arthopyrenia fraxini Massal. (including f. orbicularis Massal. and f. rufidula Massal.), A. salicis Massal., Verrucaria nitescens Salwey and V. subcerasi Vainio.

An account of the lichens of the Ben Lawers–Meall nan Tarmachan area is provided. After re-evaluating the older records, 431 species are accepted as having been reliably recorded from high ground of which 118 are reported for the first time. These include Bacidia carneopallida, Caloplaca ammiospila, C. approximata, Catapyrenium daedaleum, Ionaspis cyanocarpa, Micarea crassipes, Ochrolechia inaequatula, Omphalina pararustica, Phaeophyscia endococcina, Porocyphus rehmtcus, Protolhelenella leucothelia, Stereocaulon tornensis, and Toninia fusispora new to the British Isles. Rarities are particularly numerous on the summit cliffs and in the Lochan nan Cat corrie. An ecological description of the lichen flora of the main localities is provided. Evidence is advanced that this concentration of arctic-alpine lichens is a result of the coincidence of strongly calcareous bands within the mica-schist, an unusually severe climate, and the rugged topography which provides extensive outcrops right to the summit. The lichen flora is probably the most outstanding feature of the botany of Ben Lawers; this survey confirms the international importance of the area. One new species, Pyrenopsis multispora Coppins, is described and three new combinations are made: Bacidia carneopallida (Müll. Arg.) Coppins, B. tetramera (de Not.) Coppins, Kiliasia scotinodes (Nyl.) Coppins.

This paper reassesses the southern temperate South American and Australasian species of Nephroma, analyses their chemistry and provides a key to the 14 species and three varieties accepted. N. occultum from North America is also discussed due to its close relationship to N. microphyllum and N. papillosum. Three pairs of morphotypes are described for the first time: N. analogicum-N. chubutense, N. kuehnemannii-N. microphyllum and N. skottsbergii-N. papillosum. N. papillosum sp. nov. and N. skottsbergii sp. nov. from Chile and Argentina are newly described. N. lobuligerum and N. lepidophyllum are reduced to varietal rank. N. lyallii is placed in synonymy with N. plumbeum and a new combination N. plumbeum var. isidiatum (J. Murray) F. J. White & P. James is made.

Verrucaria aranensis McCarthy and V. knowlesiae McCarthy are described as new from limestone in western Ireland. Verrucaria mulabilis Borrer is an illegitimate name; moreover, a number of British specimens attributed to it are V. dolosa Hepp. A key to minute-spored, terrestrial saxicolous Verrucariae is provided in which V. subumbrinula Vainio and V. anzianoides Magnusson are reduced to synonymy under V. naeviformis Vainio and V. arctica Lynge, respectively.

Two new lichen species Peltigera frippii Holt.-Hartw. and P. scabrosella Holt.-Hartw.are described. Their morphology, chemistry, and ecology are discussed, and their distribution in Norway is mapped. New chemical data are also given for the related species P. lyngei Gyelnik, P. malacea (Ach.) Funck, P. neckeri Müll. Arg., and P. scabrosa Th. Fr.

The genus Haematomma Massal. (type species: H. ochroleucum (Necker) Laundon) includes the pantropical and subtropical H. puniceum group, but differs in a range of characters including ascus structure, paraphyses, and chemistry from Ophioparma Norman (type species: Ophioparma ventosa (L.) Norman). The differences are such that a new family Ophioparmaceae Rogers & Hafellner is described with Ophioparma as its type genus, and the circumscription of the family Haematommaceae Hafellner is emended to take these changes into account. The combination Rosellinula kalbii (Hafellner) comb. nov. is proposed.

The nature of elm bark as a lichen substratum is considered; a method of bark pH measurement is described and examples show the effects of the environment on bark pH. A summary of elm taxonomy includes a field key to the identification of elms. An estimation of the degree of restriction of 97 lichen species found on elms is given together with distribution maps of the most restricted species, and a list of lichens recorded on elm. The spread and control of Dutch Elm Disease is discussed. The future of elms and the consequences for the more highly restricted lichen species are reviewed. Bacidia incompta, Collema fragrans, Gyalecta flotowii, G. ulmi, and particularly Caloplaca luteoalba and Cryptolechia carneolutea, are most at risk from the widespread loss of elms.

Verrucaria simplex McCarthy is described as new from northern England. Verrucaria granulosaria Clauz. & Zehetl. and V. papillosa Ach. are recorded for the first time in the British Isles.

Ninety-two specimens (of 26 species belonging to four genera) of the Graphidaceae were collected from various areas in Japan. Their phycobionts were isolated and studied taxonomically. The phycobionts were all identical and identified as Trentepohlia lagenifera, an alga that is widely distributed in Japan. It occurs freeliving on bark and stones under humid conditions. This alga forms zoosporangia abundantly in the field and in culture but not in the lichenized state.

The name Diploschistes gypsaceus is lectotypified on material of a saxicolous taxon, while a widespread terricolous taxon, frequently named D. gypsaceus, must be named D. diacapsis. Synonyms are listed and the characters of both species reviewed.

Caloplaca lucifuga Thor sp. nov. is described and reported from Denmark, England, France, Germany, Italy and Sweden. It is only found sterile and is mainly characterized by its endophloedic, sorediate thallus, chemistry and habitat. In Sweden, the species is found in dense wooded pastures dominated by Quercus robur, growing on the bark of very old trunks of Quercus robur or, rarely, Tilia cordata. Outside Sweden, it is found also on Castanea sativa, Fagus sylvatica and Ulmus glabra.

In the recently deglaciated zone of a valley glacier in Central Ellesmere Island the mean period of time before the onset of colonization on bare rock surfaces was estimated to be about 80 years. The first species to establish was Xanthoria elegans, followed by Lecanora crenulata and Umbilicaria virginis approximately 20 years later. Summer temperature appeared to be one factor which affected lichen establishment in recently deglaciated bare areas in the High Arctic. Warmer microsites were identified as preferred locations for thallus establishment; these, therefore, constitute ideal sites for studies of thallus initiation under natural conditions. Following the retreat of a glacier from its most advanced Little Ice Age position, 16 species of saxicolous lichens have become established on bare rock debris in the icefree zone, but in nine transects only five species had a constancy of 80% or more. Lichen diversity in this successional photocommunity was comparable to that in a nearby pre-Little Ice Age landscape with more varied substrata.

A photosymbiodeme is described for Peltigera venosa. One member consists of small black squamules containing cyanobacteria whereas the other, the more familiar thallus of the species, contains green algae. New aspects of morphogenetic influences are discussed.

The anatomy of Chondropsis semiviridis (Nyl.) Nyl. shows adaptations to a vagrant life form and sub-arid habitat. The differential swelling of the thick upper cortex and the medulla is responsible for the rolling movement of the thallus under successive wet and dry conditions.

A new species of Sarrameana, S. tasmanica Vězda & Kantvilas, is described from Tasmania. The taxonomic relationship of this species with S. paradoxa Vězda & P. James from New Caledonia is discussed.

Specimens of Dictyonema glabratum from various elevations in the Venezuelan Andes show clear differences in morphology. Optimal development of thalli is attained in the lower Paramo at 3500–3600 m; at the upper altitudinal limit of distribution at about 4300 m only poorly developed thalli are found; in the montane forest zone at about 1700 m the thalli attain about half the average surface area and two thirds of the thickness of those in the optimal habitat. The histological structure of the thalli also shows significant differences. The relative volumes of photobiont to mycobiont, as an indicator of the relationship autotrophism/heterotrophism, is 1.6:1 in specimens from the upper Paramo; 0.9:1 in open habitats on the lower Paramo; 0.5:1 in shaded habitats; and 1.4:1 in the montane forest. The three altitudinal morphotypes are not only distinguished by structure but also by carbon dioxide gaseous exchange patterns. Specimens from the optimal habitat exhibit the highest photosynthetic capacity. The respiration activity reflects a homeostatic adjustment to the prevailing temperature regime: the respiration of specimens from 4300 m at 1°C approximates to same intensity as that of D. glabratum from the lower Paramo zone at 6°C. Nevertheless, metabolic homeostasis is only possible over a narrow temperature amplitude. On account of the large heterotrophic component in lichens, at altitudes below 1500 m where the temperature average is 20°C or more and the nocturnal temperatures are constantly high, the dry matter consumption due to respiration would become extremely high. This suggests that D. glabratum may be limited in its downward distribution by an increasingly unfavourable carbon budget.

Soredia of Peltigera didactyla were cultivated under laboratory conditions in a culture chamber. The developmental stages were observed by light microscopy and macrophotography until thallus formation was achieved; this occurred after a period of five months.

Two-years' observation of Athelia arachnoidea lesions in the field showed that they are long-lived perennial structures. In the Sheffield area, central parts of lesions become recolonized by Lecanora conizaeoides only after secondary infection by the lichen parasite Lichenoconium erodens followed by an invasion of the green alga Desmococcus naegelii. A. arachnoidea is active only during the winter months probably as a result of the higher humidity. The role of the sclerotia remains obscure.

Phycobiont cells of Parmelia laevigata contain chloroplasts with pyrenoids penetrated by a reticulum of tubules. The occurrence and significance of such tubules in algae is discussed. Although these tubules collapsed in desiccated cells, their lumen reappeared on rehydration. However, in such desiccated cells, pyrenoglobuli did not become peripherally located within the pyrenoid, except when damage occurred to the pyrenoid matrix. Rehydration of desiccated cells reduced the number of pyrenoglobuli per pyrenoid.

Thirty-five species of lichens were collected from nine locations on or adjacent to the Navajo Indian Reservation in the southwestern United States. Wool was dyed using the traditional boiling water and ammonia fermentation methods. An additional method was developed using a solvent to extract lichen substances and dye wool, cold; this dimethylsulphoxide extraction method is described and the resulting dye colours were sometimes different. Over 155 individual dye tests were made on sheep's wool; a correlation of dye colour with lichen substances reported for the species was attempted. Predominant dye colours were tan, but yellow, orange, pink, purple, and blue-grey were also produced. These colours were further altered by modifying: (1) fermentation time; (2) dyeing time, temperature, or pH level; (3) exposure to light; and (4) subsequent additional extractions using the same method or different methods. Dyed wool samples, tested for stability in sunlight, generally faded to some degree and some changed colour. Most dyes obtained through the dimethylsulphoxide extraction method were light stable.