During a revision of epiphytic species of the Lecanora subfusca group in the Czech Republic, nine taxa were recorded. Lecanora cinereofusca, although reported for the first time from the country here, is considered to be extinct, as is L. horiza. Lecanora circumborealis has been excluded from the list of Czech lichens. Lecanora rugosella and L. subrugosa respectively are regarded as extreme morphological forms of L. chlarotera and L. argentata, ecologically derived through nutrient enrichment (eutrophication). Lecanora laevis is regarded as a morphotype of L. horiza. An identification key is provided. The importance of the amphithecium and cortex type as taxonomic characters is discussed in detail. Several new secondary metabolites belonging to the terpenoids, discovered during an investigation of lichen compounds, proved to be taxonomically important. The abundance of L. allophana and L. chlarotera has decreased during the second half of the 20th century, but L. pulicaris has expanded. The main reasons for these changes are air pollution and acidification of substrata; L. pulicaris, for example, formerly a predominant lichen on acid-barked trees, today grows mainly on trees with slightly acidic or subneutral bark.

The crustose genus Staurothele (Verrucariaceae, Ascomycota) is a common component of the lichen flora from subneutral to alkaline silicate rocks in temperate to cold-temperate climates. Our field study in the karst system of northern Vietnam showed that it is also common on dry to humid limestone in the wet tropics. Molecular data revealed that species of Staurothele from Vietnam belong to an unnamed clade sister to the genus Endocarpon, together with the tropical Australian species Staurothele pallidopora and Staurothele diffractella, a North American species recently transferred to Endocarpon based on molecular data. The genus Willeya is here resurrected for this clade of crustose epilithic Staurothele with pale ascospores. Eight new combinations are proposed and three new species of Willeya are described from Vietnam. Sampling tropical members of a lichen family previously mostly known from temperate areas contributed significantly to improving its generic classification.

Non-saxicolous lecideoid lichens form a diverse and polyphyletic group of species with a worldwide distribution. The phylogenetic relationships of the taxa and major clades are still largely unresolved. Here we introduce a new genus Palicella Rodr. Flakus & Printzen for Lecidea glaucopa Hook. f. & Tayl. and two closely related species. Our molecular phylogenetic results, based on maximum likelihood and Bayesian phylogenetic trees, and a combined dataset of five gene loci (ITS, nrLSU, mrSSU, RPB1 and RPB2), indicate that Palicella forms a monophyletic clade sister to Lecanora symmicta and Pyrrhospora quernea. The new genus is characterized by biatorine apothecia, which are often darkened (by the pigment Cinereorufa-green), an exciple of radiating, narrow hyphae with strongly elongate lumina, a hymenium with branched and sparsely anastomosed paraphyses, an ascus with a broad axial body surrounded by a distinct darker staining layer, and narrowly ellipsoid ascospores. Atranorin is present in all, usnic acid in two and pannarin in one species of the genus. Three new combinations are proposed: Palicella filamentosa (Stirt.) Rodr. Flakus & Printzen, P. glaucopa (Hook. f. & Taylor) Rodr. Flakus & Printzen, and P. schizochromatica (Pérez-Ortega, T. Sprib. & Printzen) Rodr. Flakus & Printzen. The molecular phylogenetic analysis confirms that Lecidea hercynica Hauck & Schmull is a synonym of P. filamentosa. An identification key to the species is provided.

Ramalina celastri is a highly variable, widely distributed pan-subtropical lichen species. In Australasia the species had been separated into two subspecies; R. celastri subsp. celastri and R. celastri subsp. ovalis. This study compares morphological variation, substratum preference and sequences of the internal transcribed spacer (ITS) and intergenic spacer (IGS) regions of ribosomal DNA from a range of specimens from New Zealand and one from Australia. Bayesian and ML trees generated using the sequence data form two well-supported clades corresponding to the two previously recognized subspecies. Molecular, morphological and geographical differences support the recognition of R. ovalis at the species rank.

A revision of corticolous Mazosia specimens showed that four species are present, all differing from the foliicolous taxa in the genus. One of them is widely distributed in the tropics and the others are, as far as is known, neotropical. Three species are co-occurring in NE Brazil. They can be distinguished as follows: M. leptosticta (Nyl.) Sparrius has longer ascospores (22–35×4–7 µm) than the other species, M. endonigra A. A. Menezes, M. Cáceres & Aptroot sp. nov. has sessile apothecia on a smooth thallus and occasionally also sessile pycnidia, M. carnea (Eckfeldt) Aptroot & M. Cáceres comb. nov. has immersed apothecia and a smooth thallus, and M. viridescens (Fée) Aptroot & M. Cáceres comb. nov. has distinct verrucae on the thallus. Descriptions are given and an identification key is presented to all Mazosia species with 3-septate ascospores, which includes all corticolous species known so far.

The following new species of Arthoniales are described from Rondônia: Alyxoria fuscospora with 3-septate clavate ascospores of 20–23×4·5–5·5 µm having a gelatinous layer soon appearing evenly brown (also known from other tropical countries). Chiodecton complexum with discrete soralia, immersed apothecia in branched lines and 3-septate ascospores (26–)33–40×2·5–3·5 µm. Coniarthonia rosea, similar to C. pulcherrima but with the apothecia pink and more irregular in outline and the ascospores 13–16×5·5–6·5 µm. Cresponea flavosorediata with yellow-olive soralia, apothecia with yellow pruina and 7–9-septate ascospores, 26–38(–50)×5·0–6·5 µm. Cresponea lichenicola, lichenicolous on a Pyrenula, with 0·1–0·3 mm wide apothecia with yellow pruina. Eremothecella helicella with helicoid curved c. 17–29-septate conidia c. 70–95×2 µm long if uncoiled, with septa 3–6 µm apart. The Arthoniales are a speciose component of the lowland rainforest of Rondônia. A key is provided to the corticolous species of most groups of Arthoniales found in Rondônia. The foliicolous species found so far are listed. Most are new records for Rondônia. Chrysothrix occidentalis is new to the Neotropics.