A revision of the Lecanora saligna-group is provided, based on specimens mainly from western and central Europe. Four new Lecanora species related to L. saligna are described: L. calabrica, L. coppinsii, L. pseudosarcopidoides and L. subsaligna, as well as a new variety, L. albellula var. macroconidiata. The species treated have in common relatively short and ± curved or bacilliform conidia and/or isousnic acid as a secondary metabolite. Species without isousnic acid, containing exclusively filiform conidia are excluded. Notes on various types of conidia (macroconidia, microconidia, mesoconidia and leptoconidia), morphology, ecology, chemistry and distribution are given and a key to the treated species is provided. Detailed descriptions are presented for eight related species in order to highlight the distinguishing characters.

The morphological circumscription of selected Central European freshwater species in the lichen genus Thelidium was re-examined against the background of a molecular phylogeny based on ITS sequences. Molecular data reveal a close relationship between Thelidium methorium, T. pertusatii and Verrucaria latebrosa contradicting the traditional separation of Verrucaria and Thelidium by ascospore septation. Thelidium methorium and T. pertusatii are closely related species. The distinction of Thelidium methorium and T. submethorium was supported both by differences in ITS sequences and morphology. Thelidium minutulum, T. pluvium and T. zwackhii form a distinct clade with small perithecia and a thin or absent involucrellum. Thelidium rehmii and T. minutulum differ morphologically only in larger variability of ascospore length and the arrangement of photobiont cells, but are clearly separated by their ITS sequences as well their ecological requirements. An identification key for epilithic freshwater species of Thelidium in Central Europe is given, a lectotype for T. pertusatii is chosen, and detailed remarks for each species are provided.

Examination of Rinodina specimens from the Cape Verde Islands revealed three new species, which are described here: Rinodina capeverdeana Giralt & van den Boom, R. inspersoparietata Giralt & van den Boom and R. polymorphaespora Giralt & van den Boom. Additional information is given for six further species, of which five are new records for the archipelago. Rinodina punctosorediata Aptroot & Sparrius was found to be conspecific with R. stictica Sheard & Tønsberg.

Three new species of the lichen genus Caloplaca (Teloschistaceae) from India are described. Caloplaca jatolensis belongs to the Triophthalmidium section, while C. pseudisteroides and C. subleptozona belong to the Sideritis group.

Bactrospora flavopruinosa F. Berger & Aptroot is described as a new lignicolous lichen from Bermuda, characterized by the yellow pruinose apothecia and filiform ascospores.

Two lichenicolous species are discussed: the recently described Unguiculariopsis nephromae, which occurs on Nephroma species in Canada, Fennoscandia, North America and Russia, is combined into Protounguicularia; and Hyalopeziza rapax sp. nov. is described from Pseudocyphellariacrocata in Alaska. In discussing generic placements, it is concluded that the species now known as Olla transiens is better accommodated in Protounguicularia and the species is combined into that genus. Attention is drawn to variability in general appearance of P. nephromatis, particularly the occurrence of both superficial and erumpent apothecia in the same species.

Growth rates and the ability to date an organism can greatly contribute to understanding its population biology and community dynamics. 1n 1954, V. N. Andreev proposed a method to date regularly branched members of Cladonia, a fruticose lichen, using total thallus length and number of internodes. No research, however, has demonstrated the reliability of this technique or compared its estimates to those derived by other means. In this study, we demonstrate the utility of 14C/C ratios to determine lichen age and growth rate in Cladonia stygia (Fr.) Ruoss collected from north-western Alaska, USA. The average growth rate using 14C/C ratios was 6·5 mm yr−1, which was not significantly different from growth rates derived by Andreev's internode method (average = 6·2 mm yr−1); thus, suggesting the reliability of Andreev's simple field method for dating lichens.