Microsatellite markers can provide valuable information about gene flow and population history. We developed and tested new microsatellites for the nitrophilic lichenized fungus Xanthoria parietina and studied its genetic diversity and structure within the urban area of Munich, Bavaria. We compared its local genetic pattern with that of its photobiont partner Trebouxia decolorans, for which existing microsatellites were applied. For comparison, a reference site with clean air was included in the sampling. We found support for three genetic clusters in the fungus X. parietina, which occurred intermingled in collecting sites. There was a high degree of admixture within fungal populations and individuals, and analysis of molecular variance revealed a lack of population structure in the mycobiont. The Trebouxia photobiont, in contrast, exhibited structured populations which grouped into two to five genetic clusters, and individuals showed less admixture than in the mycobiont. This indicates that the two lichen partners differ in their ability to move around in the landscape. The microsatellite markers we report are polymorphic and are suitable for population genetic studies.

Gneiss inselbergs in the Caatinga region of Ceará in equatorial Brazil are literally covered with a wide diversity of caloplacoid lichens. This includes two closely related new saxicolous species of Caloplaca, both with the aspect of a Lecanora of the subfusca-aggregate: C. lecanorocarpa has a grey areolate bullate thallus with atranorin on a black prothallus, grey thalline apothecium margin, sessile apothecia with glossy dark brown disc, and ascospores of 10–12×5·0–5·5 μm, with a 5·0–5·5 μm thick septum; and the similar, related C. lecapustulata which mainly differs by the rimose thallus with irregular mushroom-shaped pustules. The phylogenetic position of the two new species has been assessed to be within the Caloplacoideae. A key to all tropical lecanoroid Caloplaca species is provided.

Using ITS nrDNA sequence data, the Caloplaca cerina group (Teloschistaceae) is defined here as a monophyletic, but internally richly branched lineage. The group is also characterized by a combination of morphological and anatomical characters. Its internal lineages are supported by phenotypic characters in addition to ecology and distribution. Within the large C. cerina group, we have found at least 20 phylospecies in the temperate zone of the Northern Hemisphere. Two species complexes do not produce any vegetative diaspores: the polyphyletic, corticolous Caloplaca cerina s. lat. (six separated cryptic or semi-cryptic species) and the monophyletic C. stillicidiorum s. lat. that grows mainly on plant debris, small shrubs and bryophytes and consists of at least four internal lineages. All lineages producing vegetative diaspores (soredia, blastidia, isidia or lobules) are phenotypically characteristic and represent fairly easily distinguishable species: C. chlorina, C. isidiigera, C. monacensis, C. subalpina, C. thracopontica, C. turkuensis and C. ulmorum. Only the North American sorediate C. pinicola possibly represents an aggregate of species. Caloplaca sterilis is described as a new species. A key to the phenotypically distinguishable species is provided.

Lectotypes are designated for C. albolutea, Caloplaca cerina f. coronulata and for C. monacensis. The Australian C. hanneshertelii belongs to this group, but this and other possible species from the Southern Hemisphere are not treated here in detail. Some species traditionally placed in the C. cerina group due to their similar morphology are excluded here on the basis of our phenotype examinations and molecular data. Caloplaca albolutea, C. mydalaea and C. virescens are uncertain taxa and their identities still remain unclear.

A new taxonomy of the Caloplaca citrina group in the Black Sea region is presented. It is based on the nrDNA ITS molecular data, chemistry (anthraquinone contents) and 20 morphological characters. Six species previously known in the region are accepted: Caloplaca arcis, C. calcitrapa, C. dichroa, C. flavocitrina, C. geleverjae, C. limonia. Five new species are described: Caloplaca arcisproxima, C. austrocitrina, C. communis, C. confusa and C. nigromarina. Seven further species, Caloplaca britannica, C. citrina, C. marina, C. maritima, C. microthallina, C. ora and C. phlogina are also treated briefly. Some maritime species known from the Atlantic coast of Europe are absent from the region, and, surprisingly, Caloplaca citrina s. str. could not be confirmed from the study area. A key to the species present in the region is provided, although morphological characters are of very limited value in this group. The variability and taxonomic importance of particular features are discussed. No significant differences in secondary chemistry were observed among the species.

Many examples of convergence and some semi-cryptic species were revealed by molecular data. The term ‘semi-cryptic species’ is introduced here into lichenology for those species which cannot be clearly diagnosed by their morphology, but which are determined by other characters, mainly by their ecology and distribution. We propose to describe formally such species, in spite of difficulties with subsequent morphological identification.

The xanthorioid taxa Xanthomendoza borealis and Xanthoria mawsonii are revised using morphological, anatomical, secondary chemical, and molecular characters. We conclude that most specimens determined as X. mawsonii from the Antarctic are conspecific with specimens labelled X. borealis from the Northern Hemisphere. Some specimens named X. mawsonii from the Antarctic are wrongly determined specimens of Xanthoria candelaria (L.) Th. Fr, including the holotype of Xanthoria mawsonii C. W. Dodge. Accordingly, Xanthoria mawsonii C. W. Dodge is a synonym to Xanthoria candelaria (L.) Th. Fr. The only available correct name for the bipolar species, which comprises material previously determined as X. borealis and X. mawsonii, and is distinct from the more widespread taxon X. candelaria, is Xanthomendoza borealis (R. Sant. & Poelt) Søchting, Kärnefelt & S. Kondratyuk.

Caloplaca concreticola is described here as new. It is a morphologically well-characterized, sorediate species of the subgenus Pyrenodesmia, that comprises a part of the ‘‘black-fruited’’ taxa with an absence of anthraquinones in their apothecia. Currently it is known only from concrete and always occurs close to water (mainly on the walls of water channels). Analysis of nuclear ribosomal ITS sequence data of the new species, together with most European species of the subgenus, supports the recognition of the new species as a monophyletic taxon within the Pyrenodesmia clade.

Caloplaca badioreagens is a new endolithic species of subgenus Pyrenodesmia characterized by a greyish brown, K+ reddish brown epithecium, and simple, non-capitate paraphyses. It is readily distinguishable from other endolithic Pyrenodesmias (C. agardhiana, C. alociza, C. erodens) by the presence of an unknown lichen substance in the excipulum and the subhymenium, forming large, rectangular crystal plates in GAW and GE. The new species was collected on hard limestone in three localities of central and southern Italy.