We investigated the phylogenetic relationships in the cyanolichen family Placynthiaceae to test the current generic delimitations, where the monotypic Collolechia is currently accepted as distinct, based on differences in ascospores, ascus apex characteristics and the leprose thallus. Bayesian and maximum likelihood phylogenetic analyses of two sequence marker datasets confirmed that Collolechia caesia is nested within Placynthium, and should be called Placynthium caesium (Fr.) Jatta. We reassessed the spore and ascus characteristics and showed that Placynthium caesium falls well within the variation in Placynthium and is thus yet another example of a species that differs from close relatives by its crustose-leprose thallus structure.

Reports of ‘Psoroma sphinctrinum’ from Palaeotropical areas are shown to represent instead species of the genus Gibbosporina, which is described here as new to science. This genus is superficially similar to tripartite, austral Pannaria species, such as the species now referred to as Pannaria sphinctrina (Mont.) Tuck. ex Hue. A phylogram based on an analysis of the nuclear large subunit rDNA (LSU) locus shows that Gibbosporina is instead a clade in a Pannariaceae branch referred to as the ‘Physma group’, a most unexpected addition to Pannariaceae dealt with by several previous studies. Genera assigned to this group have very contrasting general appearances. However, this diverse group shares distinctly ring-like thalline excipular margins; strongly amyloid internal ascus structures; well-developed perispores which have irregular gibbae and/or nodulose or acuminate apical extensions, but not verrucae; lacks TLC-detectable secondary compounds and have tropical distributions. Gibbosporina is the only tripartite genus in the group, with distinct, nodulose, placodioid, mini-fruticose to mini-foliose cephalodia with a high diversity of Nostoc cyanobionts. The cyanomorphs can apparently exist independently in some cases, although the apothecia on such cephalodia on a specimen from Réunion were unexpectedly found to belong to the chloromorph. The genus and related genera forming the ‘Physma group’ are probably evolutionarily old, and their weak affinity to the remaining part of Pannariaceae, concentrated in the Southern Hemisphere, is discussed. The genus includes 13 known species, and the generitype is Gibbosporina boninensis from the Japanese Ogasawara Islands, originally described as Psoroma boninense and recombined here. The following 12 species are described here as new to science, seven of them with molecular support in an LSU and ITS-based phylogram: Gibbosporina acuminata (Australia, the Philippines), G. amphorella (New Caledonia), G. bifrons (Malaysia, New Caledonia, the Philippines, Solomon Islands), G. didyma (Mauritius, Réunion), G. elixii (Australia), G. leptospora (Australia, Papua New Guinea), G. nitida (Australia, Papua New Guinea, the Philippines), G. mascarena (Mauritius, Réunion, Sri Lanka), G. papillospora (the Philippines), G. phyllidiata (Solomon Islands), G. sphaerospora (Australia, Indonesia, Malaysia, the Philippines, Samoa, and with Psoroma sphinctrinum var. endoxanthellum as a new synonym), and G. thamnophora (Australia and the Philippines). Except for the phyllidiate G. phyllidiata and for G. thamnophora which has cephalodia adapted for vegetative propagation, the species are all primarily fertile. A key for determining the species is provided.

The diversity of the Trypethelium eluteriae group in Thailand was studied using molecular (ITS and mtSSU rDNA sequences), morphological, and chemical data. Three species were recognized, T. eluteriae, T. platystomum, and T. subeluteriae, with the latter two being new records for Thailand. The separation of the three species, which have sometimes been regarded as synonymous, is supported by molecular and phenotypic characters. The chemical profiles of the three species are distinct, while ascospore size, often used to distinguish species in the group, shows some overlap.

Sulzbacheromyces is a recently erected genus in Lepidostromatales, differing from Lepidostroma in the crustose thallus. After the initial discovery of S. caatingae, the only species to be found in Brazil so far, a large quantity of additional data and ITS barcoding sequences for this taxon from a much broader geographical range and different habitats was collected. Phylogenetic analysis under a maximum likelihood framework demonstrated that all specimens are genetically uniform, showing no variation in their ITS, suggesting that S. caatingae has a wide ecological amplitude beyond the Brazilian Caatinga and Atlantic Forest biomes. Detailed descriptions and illustrations of the species are presented, including a map showing the distribution of S. caatingae in the Brazilian semi-arid region and the north-eastern Atlantic rainforest.

Usnea is a cosmopolitan genus of lichen-forming Ascomycota (Parmeliaceae, Lecanorales). This hyperdiverse genus remains poorly known, especially in tropical regions, and recent efforts have been made to clarify the species concepts and describe the diversity of species. We describe five new species from tropical South America based on morphological and chemical features supported by molecular data from the ITS rDNA, nuLSU, RPB1 and Mcm7 markers. Usnea clerciana is a Galapagos endemic characterized by inflated branches holding elongated tubercles, excavate soralia and/or apothecia. Usnea aranea and U. subaranea share inflated branches with numerous papillae and a loose arachnoid medulla, but differ in the minute and irregular soralia in U. aranea, that are circular and excavate in U. subaranea. Usnea rubriglabrata and U. subglabrata are characterized by inflated branches with excavate soralia, with a reddish cortex pigmentation in U. rubriglabrata that is lacking in U. subglabrata. Usnea aranea, U. rubriglabrata, U. subaranea and U. subglabrata are so far endemic to continental South America; the three former species are closely related and cluster in a highly supported clade, characterized by species distributed in the tropical Andes. New records for the region are provided and U. moreliana is resurrected, corresponding to the valid name for U. rubricornuta.