Two species, Cliostomum coppinsii Fryday & Kantvilas sp. nov. from Scotland, and Cliostomum praepallidum (Müll. Arg.) Kantvilas & Fryday comb. nov. from Tasmania and southern South America, are described, illustrated and discussed. Both occupy an unusual position within the genus on account of their atypically wide, ± polarilocular ascospores. Patellaria banksiae Müll. Arg., based on a collection from Australia, is lectotypified and reduced to synonymy with Cliostomum griffithii (Sm.) Coppins.

Lecanactis rubra is described as new to science. It is characterized by having rounded to irregular or lirellate ascomata, relatively wide 3-septate ascospores and by the production of gyrophoric acid and an anthraquinone. The species is known only from the type locality in the deciduous dry forests in the western part of Madagascar.

Xanthoria elegans has a broad ecological amplitude, world-wide distribution and includes morphological variants which differ markedly with respect to colour, form and frequency of apothecia. Distinctive thallus forms are associated with different habitats. Samples from two contrasting habitats were studied on Ellesmere Island in the Canadian High Arctic. Carotenoids, polyphenolic products and isoenzymes were examined to establish whether two thallus types were biochemically distinct. Pigments were comparable in both morphological variants, as were approximately half of the most frequently occurring enzyme forms. Enzymatic similarity between the two resembled that between conspecific populations of other lichens. On the basis of the chemical attributes investigated, the thallus forms did not warrant recognition as fundamentally distinct entities, but were merely variants of an ecologically versatile and extremely plastic species.

A new sorediate species of Rinodina (R. algarvensis sp. nov.) is describedfrom SouthPortugal, where it grows on siliceous rocks. It is mainly characterized by its distinctivechemistry, being the only saxicolous Rinodina species hitherto known to contain stictic, cryptostictic, norstictic and menegazziaic acids in addition to atranorin and zeorin. It is compared with R. aspersa, a morphologically similar saxicolous species, which also occurs in south-west Europe, and with R. stictica, a corticolous, sorediate, North American species that also contains the stictic acid chemosyndrome.

Twenty-six taxa of Trichotheliaceae are reported from rock, bark and leaves on Christmas Island in the north-eastern Indian Ocean. Trichothelium oceanicum P. M. McCarthy sp. nov., a common foliicolous species, is described.

Standardized lichen surveys were conducted on 849 trees in 132 ecological long-term observation plots in the Swiss Plateau and Pre-Alps: 262 lichen taxa were identified, 64 (24%) of them sorediate crustose species. Their mean percentage of the flora on individual trees and in individual plots was even higher. The mean percentage of crustose lichen species with vegetative propagules, such as soredia, was per plot significantly higher in the Pre-Alps than in the Plateau, higher in forest than in non-forest areas, and, according to the vegetation belts, lowest in the colline-submontane zone. It was found that the biodiversity of lichens could not be determined without considering the sorediate crustose lichens. Furthermore, by performing standardized surveys of all taxa, the occurrence of the following species in Switzerland was confirmed for the first time: Cliostomum leprosum, Fuscidea arboricola, Fuscidea pusilla, Hypocenomyce leucococca, Hypocenomyce sorophora, Lecanora norvegica, Lepraria eburnea, Lepraria elobata, Lepraria jackii, Lepraria obtusatica, Lepraria rigidula, Pertusaria boreahs and Rinodina griseosoralifera. Seven taxa that displayed distinctive chemistry, could not yet be identified.

The new species Peltula sonorensis is described from the Sonoran Desert. It is found in several localities throughout the Mexican part of the Sonoran Desert and belongs to a distinct group within the genus Peltula, which is characterized by fairly large (up to 15 mm diam.), umbilicate-peltate squamules, growing individually and having ellipsoid to bacilliform spores.