37 taxa are discussed, with 34 being new to Madeira. Of these, Gyalectidium filicmum Müll. Arg., Massalongia carnosa (Dickson) Körber, Physaa tnbaaoides Nyl. and Rinodina intermedia Bagl., are first records from Macaronesia. Ecology and distribution of the species are briefly outlined. Our investigation shows that the proportion of both northern temperate and tropical elements in the lichen flora of Madeira is higher than formerly known.

Santessoniella rugosa Henssen & Kantvilas is described from south-west Tasmania. The granulose to subfruticose thallus is strongly gelatinous, composed of terete, wrinkled lobes, and bears numerous small, orange apothecia. The species differs from other members of the genus in details of external and internal thallus morphology.

The lichen Lecanora schistina (Nyl.) Arnold has two kinds of conidia: filiform microconidia and obpyriform macroconidia. Both appear mixed in the same conidioma, the former being much more abundant. Sometimes these conidiomata contain a third type of conidia (microconidia) belonging most probably to a lichenicolous coelomycete living in the conidiomata of the lichen.

Twenty-six taxa of Trichotheliaceae are reported from rock, bark and leaves on Christmas Island in the north-eastern Indian Ocean. Trichothelium oceanicum P. M. McCarthy sp. nov., a common foliicolous species, is described.

The new species Peltula sonorensis is described from the Sonoran Desert. It is found in several localities throughout the Mexican part of the Sonoran Desert and belongs to a distinct group within the genus Peltula, which is characterized by fairly large (up to 15 mm diam.), umbilicate-peltate squamules, growing individually and having ellipsoid to bacilliform spores.

iNaturalist is a widely-utilized platform for data collection and sharing among non-professional volunteers and is widely employed in citizen science. This platform's data are also used in scientific studies for a wide range of purposes, including tracking changes in species distribution, monitoring the spread of alien-invasive species, and assessing the impacts of urbanization and land-use change on biodiversity. Lichens, due to their year-round presence on trees, soil and rocks, and their diverse shapes and colours, have captured the attention of iNaturalist users, and lichen records are widely represented on the platform. However, due to the complexity of lichen identification, the use of data collected by untrained, or poorly trained volunteers in scientific investigation poses concerns among lichenologists. To address these concerns, this study assessed the reliability of lichen identification by iNaturalist users by comparing records on the platform with identifications carried out by experts (experienced lichenologists) in three cities where citizen science projects were developed. Results of this study caution against the use of unchecked data obtained from the platform in lichenology, demonstrating substantial inconsistency between results gathered by iNaturalist users and experts.

A saxicolous Graphis discovered in the southern part of South Korea is described as new to science. The new species, Graphis koreana sp. nov., is characterized by a green to brownish green, thick, rimose thallus, completely carbonized proper exciple, trans-septate to submuriform ascospores and the presence of norstictic acid.

Additions and corrections are provided for the South African species of Graphidaceae tribe Graphideae with hyaline ascospores. Allographa oldayana I. Medeiros sp. nov. is described as new to science based on morphological, chemical and molecular data. The new species is characterized by lirellae with striate labia and a complete thalline margin, a completely carbonized excipulum, large, muriform ascospores, and the presence of hirtifructic acid. Allographa consanguinea (Müll. Arg.) Lücking, A. leptospora (Vain.) Lücking & Kalb, Diorygma aff. minisporum Kalb et al., Graphis crebra Vain., Gr. dupaxana Vain., Gr. furcata Fée, Gr. handelii Zahlbr., Gr. longula Kremp., Gr. pinicola Zahlbr., Gr. proserpens Vain, Gr. subhiascens (Müll. Arg.) Lücking and Platythecium sp. are reported as new records for South Africa. Allographa striatula (Ach.) Lücking & Kalb, Graphis analoga Nyl. and Gr. scripta (L.) Ach. are shown to be misapplied names that should be removed from the South African checklist. The new combination Mangoldia bylii (Vain.) I. Medeiros comb. nov. (bas. Graphis bylii Vain) is made; this represents an earlier name for M. atronitens (A. W. Archer) Lücking et al. Taxonomic notes are provided for Graphis bylii var. lividula Vain. and Gr. denudans Vain., species that are known only from their South African holotypes. Phylogenetic analyses that include new DNA sequence data from the nrLSU, mtSSU and RPB2 loci confirm the generic placements of several species for which molecular data were lacking: Allographa consanguinea, Glyphis atrofusca (Müll. Arg.) Lücking, Graphis crebra and Gr. subhiascens.

Most British collections hitherto identified as Lecidea cinnabarina Sommerf. are shown to belong to either Pertusaria pupillaris (Nyl.) Th. Fr. or to a sterile species tentatively assigned to Schismatomma as S. quercicola Coppins & P. James sp. nov. Notes are also provided on a problematical Pertusaria, resembling P. pupillaris and Lecidea cinnabarina s. str.

To clarify deep relationships among species lineages within Bacidia s. str., and to investigate the robustness of the deeper branches, we combined data from three traditionally used RNA-coding genes (nrITS, nrLSU and mtSSU) with two protein-coding genes (RPB1 and RPB2). The multigene phylogeny contained 48 newly generated sequences from the Russian Far East and all Bacidia s. str. sequences from GenBank (131 sequences). We subjected the alignments for the single and concatenated data sets to Bayesian inference (BI) and two maximum likelihood (ML) analyses (RAxML and IQ-TREE). The topologies of phylogenetic trees recovered from BI and ML analyses were highly concordant. The multilocus phylogeny of Bacidia s. str. was congruent with previous results based on nrITS sequences from the Russian Far East but with considerably higher support values for most of the deeper branches. A correlation between the recovered clades and apothecial pigments in the upper part of the hymenium and lateral exciple was observed. Based on morphological and molecular evidence, Bacidia obtecta is described as new to science. It was recovered as the sister lineage of B. elongata. The two species are alike in having up to four enlarged lumina cells along the exciple edge, but B. obtecta differs in the abundant crystals found in the upper hymenium and lateral exciple, and by having spores with fewer septa.

Two Tasmanian species of the genus Cresponea are treated: C. graemeannae Kantvilas sp. nov., characterized by a very thin, saxicolous thallus, apothecia with a thick, radially fissured margin, thinly pruinose disc, hypothecium inspersed with oil droplets, and 5–9-septate ascospores, 25–40 × 6–8 μm; and C. subpremnea (Kantvilas & Vĕzda) Kantvilas comb. nov. The latter has ascospores 30–58 × 4.5–7 μm, which distinguish it from the related C. plurilocularis (Nyl.) Egea & Torrente (ascospores 27–45 × 6–8 μm). The taxa are illustrated, discussed and compared. Cresponea litoralis Elix, based on an Australian type, is considered a synonym of Bactrospora myriadea (Fée) Egea & Torrente. A key to the species of Cresponea reported from Australia is presented.

An interesting calicioid lichen has been collected as a consequence of the study that our research group is developing in the Iberian meridional beech forests. One of these is the forest Natural Reserve “Chaparral de Montejo” (Madrid Province), which represents one of the southern biogeographic limits of Fagus sylvatica in the Iberian Peninsula. The geological substratum is Silurian clayey slate. It is located in the Supramediterranean belt of central Spain. Sclerophora peronella has been found for the first time in the Iberian Peninsula and for the third time in southern Europe. The previous records in S Europe are from Calabria (Italy) by Puntillo (1992) and from Corse (France) by Vězda (Lich. Sel. Exs. 828).

Elixia cretica T. Sprib. & Lumbsch is described as a new species from the mountains of western Crete. The second member of the previously monotypic genus and only the third member of the family Elixiaceae, it is distinguished by its surficial thallus, larger ascospores and corticolous habit. Molecular phylogenetic analysis based on a sequence of mitochondrial small subunit DNA confirms the position of the new species. We also report E. flexella from New Hampshire (USA) as new to eastern North America.

The principal goal of our study was to test whether ecologically and chemically different populations of lichens in the Physconia muscigena group belong to a single, or multiple, species. We used sequence data from three markers (ITS rDNA, mtSSU rDNA and TEF1-α) for the reconstruction of phylogenetic trees based on a sampling of mostly European and Canadian populations of P. muscigena (Ach.) Poelt, P. muscigena var. bayeri (Nádv.) Poelt and P. isidiomuscigena Essl. In addition, we sought any possible geographical or ecological trends among chemotypes and haplotypes. Results show that: 1) sequence data of ITS rDNA and TEF1-α show large genetic variation in the Physconia muscigena group, which does not correlate with geographical distribution or thallus chemistry; 2) Physconia muscigena var. bayeri and P. isidiomuscigena appear undifferentiated with P. muscigena in our phylogenetic trees, and the three species cannot be distinguished on the basis of ITS rDNA, mtSSU rDNA and TEF1-α sequences. We therefore synonymized Physconia muscigena var. bayeri with P. muscigena and we recombine P. isidiomuscigena as a variety of P. muscigena.

As part of a revision of the genus Acanthothecis s. lat. (Graphidaceae) in Brazil, an updated world key to the known species of the genus is presented. From Brazil, the following ten new species are described: A. latispora, with single-spored asci, large, muriform ascospores, and norstictic and stictic acids; A. megalospora, with single-spored asci, very large, transversely septate ascospores, and norstictic and protocetraric acids; A. multiseptata, with 8-spored asci, medium-sized and narrow, transversely multiseptate ascospores, and lacking secondary substances except terpenoids; A. norstictica, with 1–2-spored asci, large, muriform ascospores, and norstictic acid; A. oryzoides, with 8-spored asci, medium-sized, transversely septate ascospores, and norstictic acid; A. rimosa, with 2-spored asci, small to medium-sized, muriform ascospores, and stictic acid; A. roseola, with 1–2-spored asci, large, muriform ascospores, and norstictic, stictic and subnorstictic acids; A. saxicola, with 8-spored asci, small, 3-septate ascospores, and norstictic acid; A. subfarinosa, with 8-spored asci, small, 6–8-septate ascospores, and norstictic acid; and A. submuriformis, with 8-spored asci, small, submuriform ascospores, and lichexanthone. In addition, three further species are formally validated, namely A. bicellulata, A. farinosa and A. subabaphoides, and the new combination A. bicellularis is proposed, based on Acanthotrema bicellularis.