Tropical mountain forests are hotspots of biodiversity that are widely threatened by human population pressure and climate change. However, the cryptogamic species richness of many tropical mountain regions is insufficiently known, the poorly understood biodiversity of tropical African lichens being a prime example. To study the diversity of the genus Peltigera (Ascomycota, Lecanoromycetes) in East Africa, we studied lichens in a wide range of habitats on the slopes of Mt Kilimanjaro in Tanzania. Ranging from savannah to alpine heath vegetation and from natural forests to agricultural environments, 13 habitat types were sampled for lichens, which were then identified based on the nuITS genetic marker and morphology. We found eight Peltigera species on the slopes of Mt Kilimanjaro, including P. alkalicola sp. nov., P. dolichorhiza, P. polydactyloides, P. praetextata, P. rufescentiformis, P. seneca, P. sorediifera and P. ulcerata. Peltigera is most common and species-rich in the subalpine Erica forest zone, and four of the eight detected species were present only in the subalpine and alpine vegetation zones. Peltigera alkalicola was identified as a previously undescribed species, growing on trachybasaltic lava in the subalpine and alpine zones of Mt Kilimanjaro. The species resembles P. lepidophora but differs by possessing smaller thalli and peltate isidia that are distinctly dark on the lighter, tomentose lamina. Based on data from the NCBI GenBank, P. alkalicola probably also occurs in Alaska (USA) and Ningxia (China). This suggests that even though the species might generally be rare, it may have a global distribution in extreme mountain environments. For the first time, we report P. sorediifera from Tanzania and P. seneca from Africa.

The Rostania occultata species complex (‘Collema occultatum s. lat.’) is revised in Fennoscandia and found to consist of four species, all epiphytes on deciduous trees: Rostania effusa A. Košuth., M. Westb. & Wedin sp. nov., R. occultata (Bagl.) Otálora et al., R. pallida A. Košuth., M. Westb. & Wedin sp. nov. and R. populina (Th. Fr.) A. Košuth., M. Westb. & Wedin comb. nov. Rostania effusa and R. pallida are newly described from humid habitats in old-growth boreal coniferous forests, usually with a mixture of deciduous trees, and from similar areas in the subalpine birch-dominated forests of Fennoscandia. Rostania effusa is characterized by apothecia with red-brown apothecium discs and an excipulum thallinum with a simple pseudocortex and cubic to oblong, muriform spores. Rostania pallida has apothecia with whitish to pale yellowish discs and an excipulum thallinum with a distinct cellular pseudocortex, and ellipsoid, muriform mature spores that are often constricted at the centre. A lectotype is designated for Collema quadratum J. Lahm ex Körb. The new combination Rostania populina is introduced for the species recognized until now as the variety Rostania occultata var. populina (Th. Fr.) Perlmutter & Rivas Plata. A key to the six species in Rostania s. str. is included.

To facilitate population-genetic studies, we developed simple sequence repeat (SSR) markers and a molecular species identification assay for Peltigera membranacea (Ascomycota, Peltigerales), a common ground-dwelling lichen of forest and tundra ecosystems. Additional markers were developed for its Nostoc photobiont. Twenty-one fungal markers for P. membranacea were found to be polymorphic, with the number of alleles ranging from 3–21. Nei's unbiased gene diversity ranged from 0.588 to 0.640 in four significantly structured (FST = 0.059) mycobiont populations. For the Nostoc photobiont, 14 polymorphic SSR were developed, yielding 4–14 alleles each, with gene diversity ranging from 0.062 to 0.771 in four populations showing substantial population structure (FST = 0.278). The new markers developed are suitable for population genetic studies of Peltigera membranacea and of its cyanobiont, and at the same time allowed us to distinguish 98.5% of P. membranacea specimens from morphologically similar species of Peltigera.

The new genus Sinuicella, an early successional lichen, was found on bare soil in Oregon, USA. The thallus is minute fruticose, grey to nearly black, branching isotomic dichotomous, branches round, 20–90 μm wide in water mount. The cortex is composed of interlocking cells shaped like jigsaw puzzle pieces. Spores are hyaline, 1-septate, 25–40(–50) × 6.5–9(–11) μm. Maximum likelihood phylogenetic analyses on multilocus data sets, first spanning the entire order Peltigerales and then restricted to Peltigeraceae with extended sampling from Solorina and Peltigera, revealed the placement of Sinuicella outside of currently recognized genera, sister to Peltigera, with high support. Based on the phylogenetic, morphological and ecological distinctness of Sinuicella, we formally introduce a new genus represented by the single species S. denisonii. The cyanobiont of S. denisonii is Nostoc from phylogroup XL, Clade 2, Subclade 3 based on the rbcLX marker.

As part of our ongoing research on Peltigera, we recognize a morphologically and phylogenetically distinct new species, Peltigera shennongjiana L. F. Han & S. Y. Guo, from the Shennongjia region of Central China. It is distinguished from other members of the P. canina-group by the presence of abundant phyllidia and flat, branched lobules along the margin or laminal cracks, short lobes, and a pruinose, usually greyish upper surface. The various populations sampled share identical ITS nr DNA sequences, of which the ITS2 regions are characterized by a unique secondary structure. Furthermore, we provide a detailed comparison of the characteristics of P. shennongjiana with morphologically similar species and a key to Peltigera species reported from China.

Molecular inferences of three loci within a phylogenetic framework of a subset of the Pannariaceae confirm that the genus Kroswia is nested within the genus Fuscopannaria. The formal combination of the type species of Kroswia into Fuscopannaria is therefore made here, and Kroswia is reduced into synonymy with the latter genus.

Two new lichenicolous ascomycetes, Corticifraga santessonii and C. chugachiana, are described from Lobaria and Nephroma species. The new species are readily distinguished by narrow ascospores and are known from the USA, Canada and Russia. A Table with the distinguishing characteristics of all known Corticifraga species is presented.

In this investigation we utilized parsimony and Bayesian analyses of mtSSU and nuLSU rDNA sequence datasets to show that the lichenized ascomycete genera Leptochidium and Polychidium (formerly classified in Placynthiaceae) form a well-supported monophyletic group with Massalongia (Peltigerales, Lecanoromycetes, Ascomycota). This group is also supported by morphological characteristics (ascus type, ascoma ontogeny and anatomy), but does not have a formal name on any level. We describe it here as the family Massalongiaceae. Massalongiaceae is related to a group consisting of Peltigeraceae-Nephromataceae, and Lobariaceae, but the detailed relationships within this group are not resolved with convincing support.