This study re-examined the status of species of Diorygma Eshw. known from the Western Ghats using an integrative taxonomy approach that includes morphological and chemical data, as well as multigene phylogenetic analyses. Prior to this work, the two species D. karnatakense and D. dandeliense were distinguished primarily on lirellae morphology (branching pattern) and the number of ascospores per ascus. Our study of the morphology, chemistry and molecular phylogeny (mtSSU, LSU and RPB2) of freshly collected samples and re-examination of type material suggests that both names should be synonymized. Consequently, D. karnatakense is accepted as the correct name, with D. dandeliense as a newly proposed synonym. Phylogenetically, D. karnatakense is allied to D. antillarum and D. hieroglyphicum.

Five Graphis species are reported as new to Europe from the Mata Nacional do Buçaco, a region in Portugal where graphidoid Graphidaceae are abundant and diverse. The following species were identified: Graphis dendrogramma, G. duplicata, G. gonimica, G. librata and G. pyrrhocheiloides. An updated key is given to the Graphis species known from Europe. All those newly reported were identified with names corresponding to tropical species.

Peter D. Crittenden served as senior editor of The Lichenologist, the flagship journal in the field of lichenological research, for a period of two decades, between 2000 and 2019. A review of the development of the journal and the publication output during this period is provided. The number of papers published during this period (1197) matches that of all papers published under the three previous senior editors, Peter W. James, David L. Hawksworth and Dennis H. Brown, during a much longer period of 42 years from 1958 to 1999. Peter oversaw important editorial changes to the layout and content of the journal: an increased size with a modern cover design, leaving behind the classic mint-coloured cover of more than 40 years; the addition of ‘thematic issues’ and encouragement of large monographs; implementation of substantial changes to the Code, such as effective electronic publication and obligate registration of new fungal names; and more recently a new policy to reject so-called ‘single naked species descriptions’. Shortly before Peter took over as senior editor, The Lichenologist had received its first impact factor, and Peter managed to continuously increase this measure from around 0.9 to lately up to over 1.5, higher than most other competing journals. The 1197 papers between 2000 and 2019 were published by a total of 1138 different authors, more than half of whom appeared just once as author, whereas a small number participated in numerous (up to 93) papers. There was a continuous increase in the mean number of authors per paper per year, from below 2.5 to around 3.5, the highest numbers ranging between 11 and 30; still, c. 75% of all papers between 2000 and 2019 were single-authored or had up to three authors. Based on affiliations at the time of publication, two thirds of author contributions came from Europe (66%), 13% from North America, 9% from Asia and 7% from Latin America. Likewise, almost half of the study areas were located in Europe and around 10% each in North America, South America and Asia. The countries with the highest number of studies included, in descending order, the United States, Spain, the United Kingdom, Norway and Sweden. North America and Europe were over-represented in terms of author contributions, whereas Africa, Latin America, Australia and Oceania were over-represented in terms of study areas. The 1197 papers analyzed encompassed a broad diversity of topics, classified into 32 categories. Taxonomy of lichenized fungi was the most frequent component, representing the focal point in almost half of all studies, followed by phylogeny and evolution, ecology, and the taxonomy of lichenicolous fungi. Around two thirds of the currently accepted genera of lichenized fungi were treated, with a significant correlation between known species richness and the number of papers in which a genus was treated, underlining the taxonomic representativity of papers published in the journal during the past two decades. Examples of genera that were treated more frequently than expected included commonly studied model organisms, such as Lobaria, and those frequently featured in ecological or other non-taxonomic studies, such as Xanthoria. Species-rich tropical genera, particularly in the Graphidaceae, were generally under-represented. Mean number of authors per paper per volume and total number of country origins of authors per volume were the best predictors of impact factor, followed by diversity of study countries per volume, mean number of study countries per paper per volume, mean number of topics per paper per volume, and proportion of studies with phylogenetic components per volume. Individual papers that contributed to high impact factors included broad-scale revisionary treatments and worldwide keys to species-rich taxa, substantial phylogenetic reclassifications of known taxonomic groups, papers dealing with novel methodological approaches of broad interest, and broad-scale studies related to environmental change and lichen biomonitoring.

Opegrapha multipuncta and Schismatomma quercicola are two sterile European lichens reproducing only vegetatively by means of soredia. RAxML and Bayesian analyses of newly generated sequence data from the mitochondrial ribosomal RNA small subunit provide clear evidence that these two species do not belong to the Arthoniomycetes, but to the Lecanoromycetes. In our phylogenetic analyses, O. multipuncta is nested in the genus Porina (Porinaceae) as sister to P. austroatlantica, while S. quercicola is nested in the genus Schizotrema (Graphidaceae) as sister to S. zebrinum. The following new combinations are introduced: Porina multipuncta (Coppins & P. James) Ertz, Coppins & Frisch and Schizotrema quercicola (Coppins & P. James) Ertz, Frisch & Sanderson. Schizotrema quercicola represents the first record of the genus Schizotrema for Europe and the first sorediate member in this genus. The species is newly recorded from Norway. The lichenicolous habit of Arthonia invadens is confirmed.

Seven Graphis species are reported as new to Europe from the Serra de Sintra and the Planalto das Cezaredas, two regions of Portugal where graphidoid Graphidaceae are abundant and diverse. The following species were identified: Graphis cincta, G. crebra, G. handelii, G. leptospora, G. lineola, G. plumierae, and G. verminosa. Many of these share two characters: a densely inspersed hymenium and the presence of norstictic acid in the thallus. A key to the Graphis species known from Europe is provided. The possible reasons for the high, previously unknown, diversity of graphidoid Graphidaceae in this region are discussed. Global warming might be a contributory factor.

Eight species of Herpothallon are recorded from the Andaman Islands, four of which are described as new: Herpothallon coralloides, H. globuliferum, H. lutescens and H. minutum. All these new species have a non-pigmented thallus, prothallus, hypothallus and pseudisidia. Herpothallon coralloides and H. lutescens possess cylindrical pseudisidia whereas H. globuliferum and H. minutum have granular to globose pseudisidia. Herpothallon globuliferum is foliicolous. Herpothallon echinatum, H. granulare, H. granulosum and H. philippinum are reported for the first time from the Andaman Islands. A key to the Indian species is provided. Heiomasia pallescens (Graphidaceae), a byssoid taxon with a disc-shaped isidioid structure, is also described as new to science.

A new lichenicolous ascomycete, Arthonia diorygmae, is described from the thallus and ascomata of Diorygma junghuhnii. The new species is characterized by rounded to irregular, applanate to convex ascomata up to 0·3 mm in diameter, a slightly whitish pruinose disc, transversely 1-septate, hyaline to greyish ascospores (13–)14–15(–21)×5–7 µm, and its lichenicolous habitat. It is known from the subtropical region of the Western Ghats in India and appears to be widespread due to the large distribution of the host species.

As part of an ongoing inventory of the lichenized mycota of the Caxiuanã National Forest, at Ferreira Penna Research Station in the Brazilian Amazon, two species of lichenized fungi are described as new and four new combinations are introduced: Ampliotrema megalostoma (Müll. Arg.) M. Cáceres & Lücking comb. nov., Graphis brachylirellata M. Cáceres & Lücking sp. nov., Malmidea leucogranifera M. Cáceres & Lücking sp. nov., Ocellularia conformalis (Kremp.) M. Cáceres & Lücking comb. nov., Redingeria microspora (Zahlbr.) M. Cáceres & Lücking comb. nov., and Sarcographa megistocarpa (Leight.) M. Cáceres & Lücking comb. nov.

In continuation of our ongoing revisionary studies on the lichen family Graphidaceae from India, a treatment of 25 species of the lichen genera Fissurina and Hemithecium from India is presented. In our earlier work on the lichen genus Fissurina, 16 species were reported from India. In the present study, 17 additional species of Fissurina from India are recognized. Nine species, viz. Fissurina andamanensis, F. disposita, F. immersa, F. indica, F. microcarpa, F. nicobarensis, F. simplex, F. sporolata, and F. submonospora, are described as new to science. Seven species, viz. Fissurina canlaonensis, F. cingalina, F. comparimuralis, F. monospora, F. nitidescens, F. rubiginosa, and F. subnitidula, are recorded for the first time from India. One species, Fissurina sp. 1, is recorded but not formally described as new due to scanty material. Eight species in the lichen genus Hemithecium, including three new species, viz. H. kodayarense, H. longilirellatum, H. verrucosum, and five new combinations, viz. Hemithecium andamanicum, H. flabillatum, H. flavoalbum, H. flexile, and H. norlabiatum, are also recognized in the present work. A revised key for the identification of all 33 species of Fissurina and 26 species of Hemithecium so far known from India is provided.

Two new species of the lichen genus Carbacanthographis, namely C. albolirellata and C. indica, are reported from India. The two species are distinguished by their exciple character, ascospore septation and chemistry. Carbacanthographis albolirellata has a completely carbonized exciple, submuriform ascospores and no lichen substances. Carbacanthographis indica is characterized by a laterally carbonized exciple, trans-septate ascospores and by the presence of salazinic acid.

Leiorreuma subpatellulum is described as new to science. The new species has a completely carbonized exciple, an inspersed hymenium and brown ascospores with 6–12 locules, tapering at one end.

Two species of the lichen genus Carbacanthographis, namely C. marcescens and a new species, C. sorediata, are reported from India. The new species is characterized by a sorediate thallus, laterally carbonized exciple, submuriform ascospores, and salazinic and consalazinic acids in the thallus. A worldwide key to the species of Carbacanthographis is provided.

Chapsa rubropruinosa Messuti & Codesal collected in Argentina is described as new to science. The species is characterized by a thin thallus, apothecia with a pigmented disc, and transversely septate, hyaline, non-amyloid to faintly amyloid ascospores with thin cell walls. Chapsa minor is recorded for the first time from South America. The new combination Topeliopsis lomatiae (Messuti, Lumbsch & Vězda) Messuti & Mangold is proposed.

Twenty-six species recently described from Thailand are revised. Eleven taxa are reduced to synonymy with previously described species, including Leptotrema phaeosporum var. vainiona Räsänen. The following new combinations are proposed: Chapsa calathiformis (Vain.) Lumbsch & Papong, C. laemensis (Homchantara & Coppins) Lumbsch & Papong, Melanotrema melanophthalmum (Homchantara & Coppins) Lumbsch & Papong, Ocellularia albocincta (Hale) Divakar & Mangold, O. guianensis (Sipman) Divakar & Mangold, O. khunantensis (Homchantara & Coppins) Lumbsch & Papong, O. percolumellata (Sipman) Divakar & Mangold, O. subcalvescens (Nyl.) Divakar & Mangold and Ocellularia subgranulosa (Homchantara & Coppins) Lumbsch & Papong.

Thelotremoid lichens (Ostropales, Ascomycota) with a trentepohlioid photobiont in Tierra del Fuego, the Falkland Islands, the South Island of New Zealand, and subpolar islands of the southern Hemisphere are studied. Twenty-five species are accepted, with three species described as new to science: Melanotopelia blepharostoma Lumbsch & Divakar, Topeliopsis athallina Lumbsch & Mangold and Topeliopsis patagonica Mangold & Lumbsch. The new combination Topeliopsis novae-zelandiae (Szatala) Lumbsch & Mangold is proposed.

As part of our ongoing studies of the Graphidaceae in North America, we resolve the status of all taxa traditionally assigned to the genus Graphina that have been reported from the continent north of Mexico. Treatments for the North American members of Acanthothecis, Carbacanthographis, and Diorygma are presented because several species of Graphina have been reassigned to these genera, and our studies of accumulated herbarium materials revealed the existence of several previously unreported and unrecognized species. The following new combinations are made: Acanthothecis leucopepla, A. mosquitensis, A. peplophora, and A. poitaeoides. Carbacanthographis muriformis is described as new to science based on material from Florida. The following taxa are reported from North America for the first time: Acanthothecis poitaeoides,Diorygma junghuhnii, D. reniforme.

A phylogenetic study using DNA sequences of the nuclear ribosomal large subunit from 38 species is used to infer the phylogeny of species currently placed in Topeliopsis. The genus is shown to be polyphyletic; monophyly of previous and current circumscriptions of the genus are rejected using two alternative hypothesis tests. Topeliopsis meridiensis is shown to be closer to Chapsa than Topeliopsis, but additional studies are necessary to understand the circumscription of Chapsa. The new genus Melanotopelia Lumbsch & Mangold is described to accommodate T. toensbergii and T. rugosa. These species were previously regarded as aberrant in Topeliopsis because of their thin-walled ascospores and dark pigmented proper exciple. The new combination Graphis mexicana (Hale) Kalb, Lücking & Lumbsch is proposed and Graphis muscicola and Topeliopsis globosa reduced to synonymy with this species.

Eighteen species in the lichen genera Acanthothecis Clem. and Fissurina Fée (Graphidaceae) with colourless, trans-septate ascospores are recorded from India. Eight new species, namely Acanthothecis collateralis, Fissurina capsulata, F. coarctata, F. karnatakensis, F. khasiana, F. longiramea, F. taeniocarpoides and F. verrucosa, and a new variety, F. dumastioides var. salazinica, are described. Fissurina saxicola ad int., clearly distinguished from the other species is recorded, but is not formally described as new to science as the material is scanty. Acanthothecis consocians, F. globulifica, F. insidiosa and F. rugosa are reported for the first time from India. A key for the trans-septate species of Acanthothecis and Fissurina in India is provided.

Opegrapha species with muriform ascospores are revised and two species, differing only in the shape of their excipulum, are accepted: O. arabica, a widespread coastal species, and O. varians, known from mainland Yemen and Socotra. The genus Dictyographa, previously distinguished from Opegrapha by its muriform ascospores, is reduced into synonymy with Opegrapha. Dictyographa angolensis and D. sandwicensis are new synonyms of O. arabica; the type of D. cinerea was found to be a mixture of different species of the Hysteriaceae; and D. contortuplicata and D. psyllocarpa are excluded from the Arthoniales. Lectotypes are designated for D. angolensis, D. contortuplicata and D. sandwicensis.

Topeliopsis darlingtonii A. Frisch & Kalb and Topeliopsis elixii A. Frisch & Kalb from Australia and Topeliopsis meridensis Kalb & A. Frisch from Venezuela are described as new species. Thelotrema decorticans Müll. Arg. and Ocellularia subdenticulata Zahlbr. are transferred to Topeliopsis and are the correct names for T. corticola Kalb and T. vezdae Kalb, respectively. A revised key of the genus Topeliopsis is presented. Ascoconidia, produced in old ascospores of T. elixii, are described for the first time for the Thelotremataceae.