The Lepraria membranacea group is shown to constitute the genus Leproloma Nyl. ex Crombie, characterized by the presence of dibenzofurans. A full account of the genus and four species is given: L. angardianum (Øvstedal) Laundon comb, nov., L. diffusum Laundon sp. nov., L. membranaceum (Dickson) Vainio, and L. vouauxii (Hue) Laundon comb. nov. The species L. diffusum comprises var. diffusum and var. chrysodetoides Laundon var. nov. Fertile material of L. membranaceum was found in the 18th century; the morphology and chemistry of this suggests that the genus may tentatively be included in the ascomycete family Pannariaceae. Leproloma angardianum has a powdery thallus in shade but a granular thallus in sun. Lepraria arctica is a synonym of Leproloma vouauxii. The latter species contains a newly identified compound, methyl pannaric acid, and L. diffusum also contains a new compound, oxypannaric acid.

Verrucaria elaeomeleana (Massal.) Arnold s.str. is confirmed for the British Isles and its separation from V. funckii (Sprengel) Zahlbr. is discussed. Additional records are provided for V. latebrosa Körber. Verrucaria aquilella Nyl. and V. fuscocinerascens Nyl. are confirmed as synonyms of V. aethiobola Wahlenb., while V. conturmatula Nyl. is shown to be based on immature material of Polycoccum microsticticum (Leighton ex Mudd) Arnold growing on Hymenelia lacustris. The British record of V. amylacea Hepp is referred to V. praetermissa (Trevisan) Anzi, and that of V. collematodes Garov. is referred to V. fusconigrescens Nyl.

Cladonia arbuscula subsp. squarrosa (Wallr.) Ruoss and C. stygia (Fr.) Ruoss are reported for the first time from the Southern Hemisphere. Populations of C. arbuscula in New Zealand and Australia are recognized as subsp. stictica Ruoss, subsp. nov., usually containing stictic acid, norstictic acid (first report in subg. Cladina), and sometimes also the fumarprotocetraric acid complex. C. laevigata (Vainio) Gyelnik is reinstated in Cladonia subg. Cladina sect. Tenues, while C. stygia is considered to belong to sect. Crustaceae rather than to sect. Tenues. C. confusa R. Sant. is morphologically highly variable, although chemically uniform, usually containing usnic acid and perlatolic acid. An usnic acid-deficient chemodeme is reported as new to New Zealand.

Lasallia hispanica (Frey) Sancho & Crespo comb. nov. is proposed as a result of anatomical and morphological comparisons between it and the related species, L. brigantium Zsch. and L. rossica Dombr. For all three species ecological notes, data on world distributions, and a key are provided.

Fifty-five new lichen taxa from the Azores are discussed. Of these, 30 taxa are new records for Macaronesia and 15 are new records for Europe.

The terricolous lichen flora on the Dungeness shingle, in south-east England, includes an abundance of members of the Cladonia chlorophaea complex. From a detailed examination of morphological and chemical attributes, the ‘species’ present are identified as Cladonia chlorophaea s. str., C. fimbriata, C. humilis, C. merochlorophaea, C. cryptochlorophaea and C. merochlorophaea var. novochlorophaea. Cladonia fimbriata and C. chlorophaea are dominant on the younger, more seaward ridges, whilst C. merochlorophaea becomes important on the older ridges. Cladonia humilis is confined to sandy substrata.

The effects of fluoride and sulphur dioxide on the germination of ascospores of Lecanora conizaeoides, Xanthoria parietina, Physconia distorta and Peltigera canina were studied under controlled conditions. The two pollutants (H2SO3 and NaF) were dissolved in the culture medium. An improved culture technique permitted a high percentage germination (90° 0) of P. canina spores. Peltigera canina spores had the highest sensitivity to SO2 (no germination at 500 UM H2SO3). Lecanora conizaeoides spores were almost insensitive to each of the two studied pollutants (30°0 spore germination at 1000 UM H2SO3 or NaF). However, simultaneous exposure to 1000 UM H2SO3 and 1000 UM NaF resulted in no germination, indicating a synergistic effect of these products.