Five corticolous taxa of sorediate Ramalinae which occur in the tropics and subtropics are shown to comprise the tropical component of the otherwise temperate Ramalina farinacea complex. Their morphology, anatomy, chemistry, ecology and distribution are discussed. Ramalina pacifica Asah., R. nervulosa (Müll. Arg.) des Abb., R. dumeticola Krog & Swinscow and R. luciae Mohlo et al., were investigated together with an unnamed acid-deficient taxon. Ramalina nervulosa and R. pacifica are maintained as species while the remainder are considered as varieties of these species; viz. R. nervulosa var. dumeticola (Krog & Swinscow) comb. nov., R. nervulosa var. luciae (Mohlo et al.) comb. nov., and R. pacifica var. inacida var. nov.

An artificial key for the identification of 218 lichen-forming, parasitic, parasymbiotic and saprophytic fungi reported as occurring on lichens in the British Isles is provided. Agyrium flavescens Rehm, Cyphelium marcianum B. de Lesd., Scutula krempelhuberi Körber and Stigmidium solorinaria (Vainio) comb. nov. are reported from the British Isles for the first time, and three further new combinations are made: Bacidia killiasii (Hepp) comb, nov., Pleospilis ascaridiella (Nyl.) comb. nov. and Polycoccum gelidaria (Mudd) comb. nov. References to publications in which further information on the species can be found are included. Illustrations of the spores of 141 species and an index to the names of fungi and hosts are also presented.

Microglaena nidarosiensis Kindt has been rediscovered after 100 years on the west-coast of Norway. It is shown to be identical with Clathroporina calcarea W. Watson, and to belong in the genus Belonia which is placed in the Gyalectales as B. nidarosiensis (Kindt) comb. nov.

The genus Clathroporina is typified on C. olivacea Müll. Arg., and is shown not to be present in Europe. C. caudata Vězda & Vivant is transferred to Belonia as B. caudata (Vězda & Vivant) comb. nov.

The Leptogium azureum group in Europe is revised. Leptogium britannicum sp. nov., a species growing among grass on coastal rocks, is described. Leptogium azureum (Sw.) Mont. is shown to be absent from Europe, most of the material so named is Leptogium cochleatum (Dickson) comb. nov. Leptogium rivulare (Ach.) Mont. and Leptogium corticola (Tayl.) Tuck. are shown to have very limited distributional areas in central Sweden and the north-west U.S.S.R., and northern Italy and northern Yugoslavia respectively; both are in danger of extinction. The nomenclature of all species, including also Leptogium cyanescens (Rabenh.) Körber, is discussed.

Leptogium juressianum C. Tav., a species of the Leptogium lichenoides-group with hairs on the upper surface, is reported from south-west Ireland; the first record since it was described from Portugal.

The lichen vegetation of a limestone pavement in the Burren region of western Ireland is described. Species are distributed in relation to gradients of moisture, nutrient-availability and insolation; these in turn may be related to the range of geomorphological micro-features associated with karst. The majority of the 136 stands are dominated by endolithic and foliose cyanophilic lichens. Epilithic, non-cyanophilic crusts grow best on surfaces subjected to occasional bird-manuring. A successional sequence from bare rock through endolithic communities to ones dominated by epilithic, noncyanophilic species does not occur in the Burren.

Measurements of thalli of Rhizocarpon geographicum on the recent moraines of the Glacier de Valsorey and their surroundings are considered in relation to thallus growth rates and colonization following glacial recession. Photographs taken in 1975 and 1979 show that up to c. 3.5 cm diam the relation of maximum growth-rate to thallus size is approximated by a growth curve of the kind derived by Aplin and Hill, rising asymptotically towards a constant rate of radial growth (here c. 0.5 mm year−1). Growth-rates of many individual thalli fall well below the maximum. Parameters of the fitted growth curves are used to construct curves of thallus radius against time. Taken in conjunction with the field measurements these suggest two main phases of colonization, one from about 1880 to 1910, and one from about 1930 onwards. Some general considerations relating to lichenometry and lichen growth curves are discussed.

This comparative investigation on ascus fine structure and function substantiates the findings of Chadefaud (1960) and his coworkers indicating a close taxonomic relationship between the Baeomycetaceae and Leotia, a non-lichenized member of the Helotiales, rather than between the Baeomycetaceae and the Cladoniaceae and other members of the Lecanorales. Besides the distinct differences in ascus structure and function, cytological divergences were noted between the Baeomycetaceae and Leotia on one hand, and Cladoniaceae on the other. The occurrence of glycogen in the Baeomycetaceae and Leotia, but not in the Cladoniaceae and other members of the Lecanorineae, and the differences in phycobiont preference and thus in the mycobiont–phycobiont contact in the Baeomycetaceae and Cladoniaceae were discussed.

Parmotrema degelianum sp. nov. is described and the following new combinations are made: Parmotrema amaniense (Steiner & Zahlbr.) comb, nov., P. apricum (Krog & Swinscow) comb, nov., P. consors (Nyl.) comb, nov., P. durumae (Krog & Swinscow) comb, nov., P. erubescens (Stirton) comb, nov., P. glaucocarpoides (Zahlbr.) comb, nov., P. jacarandicolum (Krog & Swinscow) comb, nov., P. kwalense (Krog & Swinscow) comb, nov., P. leonis (Krog & Swinscow) comb, nov., P. pardi (Krog & Swinscow) comb, nov., P. pigmentiferum (Krog & Swinscow) comb, nov., P. pilosum (Stizenb.) comb, nov., P. poolii (Dodge) comb. nov., P. stuhlmannii (Dodge) comb, nov., P. taitae (Krog & Swinscow) comb. nov., P. tsavoense (Krog & Swinscow) comb. nov., and P. umbrosum (Krog & Swinscow) comb. nov., Parmotrema lyngeanum (Zahlbr.) Hale is reduced to synonymy with P. cristatum (Nyl.) Hale.

The cortical structure of Usnea subfloridana and algal cell division within the thallus, is illustrated and described.

Chaenotheca degelii sp. nov. is described from New Zealand. The position of the species in the genus and the chemistry are discussed briefly. Chaenotheca degelii is a lignicolous species mainly occurring in the Central Plateau of North Island, but one isolated occurrence in the South Island is also known.

Descriptions are given of two little-known species of Brigantiaea (Lecanorales, Brigantiaeaceae) which are widely distributed in New Zealand. Brigantiaea lobulata F. J. Walker & Hafellner sp. nov. is described and the following new combinations are proposed: B. tabacodes (Zahlbr.), B. nipponica (Sato) and B. austroamericana (Räsänen), combs. nov.

Seventeen saxicolous species of Rinodina are recognized in New Zealand, including five species new to science (R. gallowayii, R. jamesii, R. murrayii, R. nigricans and R. tibellii spp. nov.), one new combination (R. otagensis (Zahlbr.) comb, nov.), and six new records (R. bischoffii, R. gennarii, R. immersa, R. lecanorina, R. lecideina and R. teichophila). Names of five taxa in Buellia have been placed in synonomy. Distributional data are provided for all species. A key is given, and the various definitive spore types are illustrated.

By using a dissection technique it was demonstrated that binding of Ni2+ ions occurred to both the algal zone and fungal medulla in various species of the lichen genus Umbilicaria. The algal zone, fungal medulla and lower surface plates in Umbilicaria muhlenbergii accumulated 21, 52 and 27% respectively of the total Ni2+ ions taken up. The amount of Ni taken up varied in different species of the same genus but in general the uptake by Peltigera (over 70 μmol g−1 dry weight) was some three times that by Umbilicaria under the same conditions.

Nomenclatural notes on the following taxa are provided: Pseudocyphellaria billardierii, P. carpoloma, P. faveolata, P. rufovirescens and P. subvariabilis. Detailed chemical profiles are given for all described species of Pseudocyphellaria in New Zealand. Pseudocyphellaria ardesiaca, P. degelii, P. durietzii, P. fimbriata, P. fimbriatoides, P. gretae, P. knightii, P. maculata and P. sericeofulva spp. nov. are described for the first time.

a new sorediate species of Rinodina (R. degeliana sp. nov.) is described from north Sweden where it occurs on old Salix. Apart from its distinctive appearance it is characterized by its markedly ornamented spores and chemistry. It is compared with similar taxa in north-west Europe.

Twenty-nine species of foliicolous lichens are reported from Zimbabwe. Arthonia nigratula (Müll. Arg.) R. Sant. is mentioned for the first time in Africa, and Catillaria vandenberghenii sp. nov. is described.

The vanadium content of the lichen Hypogymnia physodes was determined in the vicinity of a power plant using heavy oil as fuel. For the chemical analysis a DC plasma emission spectrometer was used. Air dried samplesof the lichen contained between 1–4 and 57 parts per million (ppm) of vanadium. The highest concentrations were found in specimens collected less than 1 km from the power plant. Lichens collected 50 km from the plant contained less than 2 ppm of vanadium.

The genus Polythelis Clem, has been almost entirely ignored since its description in 1909. It belongs to the Pyrenulaceae and is close to Pyrenula Massal. from which it is distinguished in having a true septum (euseptum) near the base of the ascospores as well as locules (distosepta) identical to those of Pyrenula. The genus includes a single doubtfully lichenized species, Polythelis sexlocularis (Müll. Arg.) Clem. (syn. Microthelia sexlocularis Müll. Arg.), known only from the type material collected on the bark of a species of Croton, probably C. linearis Jacq., in the West Indies or southern Florida prior to 1824.