A species new to science, Micarea svetlanae, is described from the southern part of the Russian Far East based on morphological, chemical and molecular data. This species is closely related to M. isidioprasina, which also has the micareic acid, the granular-isidiate thallus with Sedifolia-grey pigment, and crystalline granules in the hymenium and thallus, but differs in the cushion-shaped thallus, the presence of Sedifolia-grey pigment in the hymenium, numerous crystalline granules in the hymenium and hypothecium and 0–2(3)-septate ascospores. The results of the phylogenetic reconstruction place M. svetlanae in the M. prasina group. Morphological features and data on ecology, distribution and secondary metabolites are presented in detail in the paper. This new lichen species is named in honour of the Russian lichenologist Dr Svetlana Tchabanenko, who devoted her life to the study of lichens of the Russian Far East.

Thirty-five species of Micarea are recorded for Tasmania. Ten are described as new to science: M. ceracea Coppins & Kantvilas (also known from Victoria and New South Wales), characterized by a thallus containing perlatolic and didymic acids, pallid apothecia and 3(–4)-septate ascospores, 10–21 × 3·5–6 µm; M. cinereopallida Coppins & Kantvilas (also known from Chile), with a granular to coralloid, goniocyst-like thallus containing superlatolic acid, pallid to piebald apothecia and (0–)1-septate ascospores, 8–15 × 2·5–5 µm; M. micromelaena Kantvilas & Coppins, similar to the widespread M. melaena but with markedly smaller, 0–1-septate ascospores, 8–12·5 × 2·5–4 µm; M. oreina Kantvilas & Coppins, characterized by a thallus of globose areoles containing gyrophoric acid, black, subglobose apothecia, and 1-septate ascospores, 11–16·5 × 4·5–6·5 µm; M. pallida Coppins & Kantvilas, similar to M. ceracea but distinguished by the presence of porphyrilic acid and relatively small, 3-septate ascospores, 9·5–15 × 2·5–4 µm; M. prasinastra Coppins & Kantvilas (also known from New Zealand), a member of the M. prasina group with a finely granular-sorediose thallus containing gyrophoric acid, unpigmented apothecia and (0–)1-septate ascospores, 7–11·5 × 1·8–3·5 µm; M. rubiginosa Coppins & Kantvilas (also known from Chile), likewise allied to M. prasina but with apothecia containing Rubella-orange pigment and ascospores 0–1-septate, 9·5–17 × 3·5–5·5 µm; M. sandyana Kantvilas, related to M. ternaria (Nyl.) Vĕzda but differing by smaller ascospores, 7–13·5 × 3·5–6 µm; M. saxicola Coppins & Kantvilas, characterized by a relatively thick, grey-brown, areolate thallus, convex, black apothecia and 0(–1)-septate ascospores, 7–18 × 4·5–7 µm; and M. tubaeformis Coppins & Kantvilas, related to M. flagellispora and with filiform ascospores, 45–100 × 1–2 µm, but differing by containing 2′-O-methylperlatolic acid and having funnel-shaped pycnidia. Ten species of Micarea are reported for Tasmania for the first time: M. almbornii Coppins, M. argopsinosa P. M. McCarthy & Elix, M. byssacea (Th. Fr.) Czarnota et al., M. contexta Hedl., M. farinosa Coppins & Aptroot, M. humilis P. M. McCarthy & Elix, M. incrassata Hedl., M. myriocarpa V. Wirth & Vězda ex Coppins, M. nowakii Czarnota & Coppins and M. pseudocoppinsii Brand et al. Also recorded for the first time for Victoria are M. alabastrites (Nyl.) Coppins and M. cinerea (Schaer.) Hedl. A key to Micarea-like lichens in Tasmania, which includes Micarea itself as well as Brianaria, Psilolechia and Leimonis, is presented. Leimonis erratica (Körb.) R. C. Harris & Lendemer and Brianaria tuberculata (Sommerf.) S. Ekman & M. Svensson are recorded for Tasmania for the first time.

A key is given to the foliose and squamulose lichens known so far from Rondônia, including also corticolous crustose lichens with a chlorococcoid alga. The foliicolous Lecanorales found are also listed. The following four new corticolous Lecanorales are described from Rondônia: Calopadia granulosa with a granular, corticate thallus and ascospores 1 per ascus, 33–38×10·5–13·0 µm; Crustospathula amazonica with irregularly capitate to nearly globose, c. 0·2–0·4 mm diam. soralia on cartilaginous stalks; Flavoparmelia plicata with a thallus containing usnic and protocetraric acids, with laminal, irregular, globose to cylindrical isidia which are often easily abraded and showing the whitish medulla, but not sorediate or postulate; Physcidia striata with ascending squamules, without hypothallus, often with laminal isidia in defined areas towards lobe tips of some, usually sterile lobes, and often with biatorine apothecia with ascospores simple to 1-septate, (6·2–)7·5–10·0×(2·5–)3·0–3·5 µm. In the whole lichen flora of the lowland rainforest region of Rondônia, the following traits can be discerned: foliose lichens amount to only 17 species (2·7% of nearly 600), 33 (5·5%) are squamulose, while the vast majority (91·8%) are crustose. Cyanobacteria are present in only 6 (1%) species. A chlorococcoid alga present in c. 100 (16%), 12 of which (2%) have a myrmecioid alga. The remainder of the species, a staggering 83%, have trentepohlioid alga, including 6 (1%) with Phycopeltis. In neotropical lowland rainforest, the vast majority of the lichens are crustose and contain a trentepohlioid alga, and the Arthoniales, Graphidaceae and pyrenocarpous lichens are the main groups, each accounting for roughly a quarter of the lichen biodiversity.

The new species Bacidia termitophila, Coenogonium coppinsii, Fellhanera termitophila, and Micarea termitophila are described from termite nests in rainforest in Rondônia and adjacent Amazonas. Lichens were found on termite mounds on the ground but most of the species were also found on termite nests on trees. This substratum may serve as the most important locality for terricolous lichens in rainforests, and the natural habitat for species known mostly from road banks.

The new genus Brianaria S. Ekman & M. Svensson is introduced for the Micarea sylvicola group, with the new combinations Brianaria bauschiana (Körb.) S. Ekman & M. Svensson, B. lutulata (Nyl.) S. Ekman & M. Svensson, B.sylvicola (Flot. ex Körb.) S. Ekman & M. Svensson and B. tuberculata (Sommerf.) S. Ekman & M. Svensson. The new genus is characterized by a chlorococcoid, non-micareoid photobiont, small, convex apothecia without an excipulum, an ascus of the ‘Psora-type’, 0–1-septate ascospores, dimorphic paraphyses, and immersed pycnidia containing bacilliform conidia. Brianaria is shown to form a monophyletic group in the Psoraceae, where it is probably the sister group to Psora and Protoblastenia.

The new species Byssoloma catillariosporum and Porina isidioambigua are described from NE Brazil. The first is reminiscent of B. leucoblepharum but differs by the consistently uniseptate ascospores. The second is characterized by tiny isidia and black perithecia with relatively large, 3-septate ascospores. Both species were found at the Área de Proteço Ambiental (APA) Morro do Urubu, an area of c. 214 hectares in the large (500 000 inhabitants) city of Aracaju. It is the only urban Mata Atlântica remnant in Aracaju, with mesophytic deciduous and semi-deciduous forest, and cerrado enclaves in isolated points.

The new species Micarea corallothallina is described from Serra da Jibóia, Bahia, NE Brazil. It has a gnarled, coralloid, isidiose thallus and pale botryose apothecia. It was found in the Serra da Jibóia, a mountainous range with a maximum elevation of 800 m on smooth bark of trees. This Mata Atlantica fragment is located in the Santa Terezinha municipality, Bahia, NE Brazil, near the Castro Alves municipality boundary. This area can be considered as a rainforest enclave surrounded by Caatinga, and belongs to a disjunct set of mountains that extend from the southern coast of the state to the North-west and North.

The new species Eugeniella nigrodisca is described from Fazenda Cafuz, Serra de Itabaiana, Sergipe, NE Brazil, where it was found on bark. It is characterized by the clavate, consistently 7-septate ascospores.

The foliicolous lichenized fungus Calopadia erythrocephala Farkas, Elix & Flakus, is described as new to science from the Atlantic submontane rainforests in Brazil. The species is very similar to C. puiggarii, but is distinguished by the presence of a red pigment in the campylidia, the darker apothecial discs and larger conidia. Fusarubin, the red pigment produced by the new species, is reported for the first time from foliicolous lichens. A world-wide key to foliicolous species of Calopadia with single, muriform ascospores is presented.

The diminutive species Micarea capitata is described from north-western Sweden. It has been found at two localities in boreal forests where it grew on the bryophyte Hylocomium splendens. Micarea capitata is distinguished by small (0·10–0·35 mm diam.) black apothecia, (0–)1-septate ascospores and a mottled, darkly pigmented hypothecium.

Bacidia coprodes (Körb.) Lettau, until now treated as a synonym of Bacidia trachona (Ach.) Lettau, is resurrected. Morphological, chemical and ecological characteristics place this species close to Toninia in the Ramalinaceae, but we retain it in Bacidia because of uncertainties in the generic taxonomy of this family. Bacidia coprodes is fairly widespread on calcareous and enriched siliceous rock in Europe and eastern North America. In North America the species has also been known under the synonyms Bacidia granosa (Tuck.) Zahlbr. (basionym: Lecidea granosa Tuck.) and Bacidia pammellii (Fink) Zahlbr. (basionym: Bilimbia pammellii Fink). Morphological and chemical features, together with molecular data, suggest that B. trachona does not belong to Bacidia, but rather in the Pilocarpaceae.

Micarea hypoviolascens sp. nov. (Pilocarpaceae) is described from an ancient woodland in western Scotland. It is the second species within Micarea known to have the olivaceous, K+ deep violet pigment (Sedifolia-grey) in the hypothecium.

The phylogeny of the Micareaceae and the genus Micarea Fr. was studied using 39 nuclear small subunit ribosomal DNA sequences. Phylogenetic analyses were carried out using maximum parsimony, maximum likelihood, and Bayesian inference. A confidence set of trees was estimated using expected likelihood weights to investigate a series of hypotheses of monophyly. Tree topologies were very similar between methods and differed only in the placement of a few poorly supported branches. The results indicate that the Micareaceae in its current circumscription belongs in the Lecanorales, but that it is not monophyletic. Psilolechia, Micarea with a ‘non-micareoid’ photobiont, Micarea sensu stricto and Byssoloma form a paraphyletic grade in this study. Micarea sensu stricto and Byssoloma (Pilocarpaceae) form a strongly supported monophyletic group, which constitutes the sister group to the Bacidiaceae. Scoliciosporum A. Massal has sometimes been considered close to Micarea, but no support was found for that hypothesis.

Byssoloma llimonae, a new species described from NE Spain, Madeira and the Canary Islands (Gomera, La Palma and Tenerife), is a mostly corticolous species, closely related to the more widespread and usually foliicolous Bapalmuia kakouettae (=Byssoloma aptrootii). The generic position of this group of species within the Pilocarpaceae is still unclear. The new combination Byssoloma kakouettae (Sérus.) R. Lücking & Sérus. is introduced.