Pannaria minutiphylla Elvebakk and P. pulverulacea Elvebakk are described here as new to science. Both species belong to the panaustral P. sphinctrina (Mont.) Tuck. ex Hue complex. Their spores, however, are more long-ellipsoid and much less verrucose than those of P. sphinctrina itself, and the species are therefore not considered to be phyllidiate and sorediate counterparts, respectively, of the latter. Pannaria minutiphylla disperses with phyllidia, which are distinctly smaller and not as erect as those of a similar Australian species, P. phyllidiata Elvebakk. Pannaria pulverulacea has the smallest vegetative propagules within this species group. They are referred to as soredia here, although they are partly corticated. This species also has the widest distribution, including wet forests of southern South America, south-eastern Australia, and from Northland to Campbell Island in New Zealand. Pannaria minutiphylla has the same distribution and often grows together with P. pulverulacea, except in southern South America, where some related material has still not been sufficiently studied. Both species are very common within their distribution areas, and previously have mostly been identified as P. microphyllizans. The latter is, however, a very different species, which instead will be studied in comparison with P. athroophylla (Stirt.) Elvebakk & D. J. Galloway.

Pannaria howeana and P. streimannii are described here as new to science. Both species are restricted to the isolated Lord Howe Island in Australia. The former is known only from one collection and the latter from two sites. Pannaria howeana is a primarily fertile species, with rather broad lobes and few rhizines restricted to the central part of the lower side of the thallus. The lower sides of the lobes have a pattern of characteristic radiating hyphae and narrowly recurved margins similar to the New Zealand lichen P. araneosa (C. Bab.) Hue, which is considered to be its closest relative. Pannaria streimannii is a phyllidiate counterpart of P. howeana. Both species share a new chemosyndrome consisting of porphyrilic acid in combination with vicanicin and leprolomin. Local endemic species are uncommon among tripartite Pannaria species, and the coarse vegetative propagules of both species appear to be an adaptation to local dispersal on a small, isolated island.

Psoroma microlepideum is reduced to a synonym of P. fuegiense. The species differs in several characters from P. pholidotum, and it overlaps geographically with the latter, which is neotypified here. These two species are now placed in the new southern South American genus Psorophorus, differing from Psoroma s. str. in being corticolous, having adpressed squamules on a distinct, dark prothallus, lacking melanins, having a thin cortical layer and a simpler IKI+ apical ascus structure. Two other widespread, panaustral species are the only ones in Pannariacae containing usnic acid. The primarily fertile species has been known as Psoroma pholidotoides, but the type contains pannarin rather than usnic acid, and the correct name for the primarily fertile taxon with usnic acid is Psoroma contextum Stirt. This is together with P. soccatum R. Br. ex Crombie is now placed in the new genus Xanthopsoroma. In addition to usnic acid, both species have a series of distinct terpenoids, some in major quantities. Like Psorophorus, they are corticolous, but have long, more or less nodulose, apical perispore extensions, and an IKI+ apical ascus tube structure which is longer and thinner, including a diffuse tholus reaction, and often an external apical sheet. Phylogenetically, these two genera are shown to be monophyletic and different from Psoroma s. str. based on an analysis of ITS and nrLSU rDNA. This analysis also shows that among the ten species focused on in this study, nine species (two in Xanthopsoroma, two in Psorophorus and five in Psoroma s. str.) are monophyletic, based on two to six sequences of each species. Psoroma hypnorum remains polyphyletic. All names now belonging in Psorophorus and Xanthopsoroma are typified.

Degelia cyanoloma (Schaer.) H. H. Blom & L. Lindblom is resurrected from synonymy and elevated from varietal rank to species. The taxon was earlier referred to D. plumbea (Lightf.) P. M. Jørg. & P. James, however, several discontinuous character states distinguish the two species. Degelia cyanoloma is characterized morphologically by having a large thallus that is pale greyish when dry, lobes that are composed of consecutive trough-shaped segments with an upper surface without squamules, no isidia or soredia, and apothecia discs that are dark reddish brown to blackish. Degelia cyanoloma has a euoceanic distribution and is known from western Europe (Norway, France, Great Britain, Ireland, Portugal, Spain). Based on results from studies of morphology, we hypothesize that D. atlantica (Degel.) P. M. Jørg. & P. James is the closest relative of D. cyanoloma among the European species of the genus whereas D. plumbea is closely related to D. ligulata P. M. Jørg. & P. James.

Pannaria leproloma is shown to be a New Zealand endemic, and is characterized by coarse isidiomorphs/isidia, a high frequency of apothecia and the presence of two cytotoxic scabrosin esters, previously unknown from Pannariaceae, and present in 40 of the samples studied. It is not a member of the Pannaria sphinctrina group, as previously thought. It has frequently been confused with a related, finely sorediate, very sparingly fertile species, which lacks scabrosin esters in more than 99 of the specimens studied. This latter species is widely distributed both in southern South America (where it is one of the most common corticolous lichens), south-eastern areas of Australia and in New Zealand. It was originally described as Psoroma isidiosum, but had to be renamed when transferred to Pannaria, and is here named Pannaria farinosa.

Pannaria isidiosa sp. nov. is newly described from montane forests in New South Wales, Australia. It is characterized by abundant globose to coralloid isidia, long-ellipsoid spores with a verrucose and citriform perispore. It is related to P. xanthomelana, but in addition to pannarin and porphyrilic acid, it contains methylplacodiolic acid and a chemosyndrome of four unidentified terpenoids.

Pannaria isabellina is transferred from Psoroma to Pannaria as it lacks the amyloid apical ascus structure characteristic of Psoroma. However, it has an isolated position within Pannaria because of its lichenized squamules developing horizontally on a thin, filmy prothallus, and its thallus chemistry characterized by the norstictic acid chemosyndrome. It also has a sclerenchymatous epicortex and a characteristic perispore with gibbose wall swellings and long flagella-like apical extensions; both characters are not often found and are still insufficiently studied within the genus Pannaria. The gelatinous, long flagella-like apical extensions of the perispores probably serve to anchor the ascospores to thin and vertical substrata; the species seems to be concentrated in forest margins of evergreen forests along the coast of Chile, except in the Valdivian rainforest region where it extends further east.

A characteristic, sterile lichen genus with homoiomerous thallus containing terpenoids is described, with one subtropical species, Kroswia crystalliferum sp. nov., occurring scattered in Africa from Kenya south to the Cape, southern India (with Sri Lanka) and Taiwan. Another temperate species, Kroswia gemmascens (Nyl.) comb, nov., is restricted to Eastern Asia. in spite of its gelatinous, homoiomerous thallus, the genus appears to belong to the Pannariaceae.