A checklist of Lichen-forming, Lichenicolous and Allied Fungi of Ecuador is presented with a total of 2599 species, of which 39 are reported for the first time from the country. The names of three species, Hypotrachyna montufariensis, H. subpartita and Sticta hypoglabra, previously not validly published, are validated. Pertusaria oahuensis, originally introduced by Magnusson as ‘ad interim’, is validated as Lepra oahuensis. The form Leucodermia leucomelos f. albociliata is validated. Two new combinations, Fissurina tectigera and F. timida, are made, and Physcia mobergii is introduced as a replacement name for the illegitimate P. lobulata Moberg non (Flörke) Arnold. In an initial step, the checklist was compiled by reviewing literature records of Ecuadorian lichen biota spanning from the late 19th century to the present day. Subsequently, records were added based on vouchers from 56 collections participating in the Consortium of Lichen Herbaria, a Symbiota-based biodiversity platform with particular focus on, but not exclusive to, North and South America. Symbiota provides sophisticated tools to manage biodiversity data, such as occurrence records, a taxonomic thesaurus, and checklists. The thesaurus keeps track of frequently changing names, distinguishing taxa currently accepted from ones considered synonyms. The software also provides tools to create and manage checklists, with an emphasis on selecting vouchers based on occurrence records that can be verified for identification accuracy. Advantages and limitations of creating checklists in Symbiota versus traditional ways of compiling these lists are discussed. Traditional checklists are well suited to document current knowledge as a ‘snapshot in time’. They are important baselines, frequently used by ecologists and conservation scientists as an established naming convention for citing species reported from a country. Compiling these lists, however, requires an immense effort, only to inadequately address the dynamic nature of scientific discovery. Traditional checklists are thus quickly out of date, particularly in groups with rapidly changing taxonomy, such as lichenized fungi. Especially in megadiverse countries, where new species and new occurrences continue to be discovered, traditional checklists are not easily updated; these lists necessarily fall short of efficiently managing immense data sets, and they rely primarily on secondary evidence (i.e. literature records rather than specimens). Ideally, best practices make use of dynamic database platforms such as Symbiota to assess occurrence records based both on literature citations and voucher specimens. Using modern data management tools comes with a learning curve. Systems like Symbiota are not necessarily intuitive and their functionality can still be improved, especially when handling literature records. However, online biodiversity data platforms have much potential in more efficiently managing and assessing large biodiversity data sets, particularly when investigating the lichen biota of megadiverse countries such as Ecuador.

Ramalina arsenii sp. nov. belongs to the R. pollinaria group and is easily recognized by its ITS barcode and several micro-morphological characters that are diagnostic in a European context: small size, less than 3 cm long; soralia developing on the underside of lobe apices; absence of excavate depressions on the lower side. Its ecological niche (i.e. rock outcrops and especially underhangs of slightly calcareous rocks, at low and mid altitudes) is also unique. Ramalina arsenii is frequent and locally abundant in France (Alps, Cantal) and Switzerland (western Alps), and is also known from Germany and the Spanish side of the Pyrenees.

A new lichen species is described from specimens growing on Fraxinus trees north of Eindhoven (the Netherlands). Morphological and genetic studies suggest that the new species belongs in the genus Catillaria, and the name Catillaria flexuosa is proposed because of its flexuose apothecia. The new species is characterized by the relatively large apothecia (up to 0.9 mm diam.) and relatively thick, knobby to ±subsquamulose, greenish, thallus. Due to their similar morphological features, C. flexuosa can be easily confused with Catillaria chalybeia, C. fungoides or C. nigroclavata, so it is therefore compared with these species. In addition, Arthonia epiphyscia is reported being a very rare species in the Netherlands.

A molecular phylogeny of the genus Byssoloma is inferred from mtSSU sequences using Bayesian and maximum likelihood phylogenetic analyses. Byssoloma subdiscordans is resolved as sister to B. citricola rather than to the B. leucoblepharum clade, the B. subundulatum group (species with a compact apothecial margin) is shown to be a monophyletic group, and three species belonging to this group are described as new to science from Hainan Province in China: B. brunneodiscum W. C. Wang & J. C. Wei, with dark brown apothecia, crystals in the excipulum and the presence of 2,5,7-trichloro-3-O-methylnorlichexanthone; B. rubrofuscum W. C. Wang & J. C. Wei, with red-brown apothecia, 3–6-septate ascospores and the presence of 5,7-dichloro-3-O-methylnorlichexanthone; B. melanodiscocarpum W. C. Wang & J. C. Wei, with pure black apothecia, a K+ olive-black hypothecium and the presence of thiophanic acid.

The new lichen species Lecidea phaeophysata is described from rocks close to the coast in Italy, Portugal, France and Ireland. Distinguishing features include Porpidia-type asci and simple paraphyses that are fuscous brown pigmented in their upper section. Its systematic position is discussed but is unclear as molecular data are lacking (all collections are c. 20 years old). Therefore, we chose to describe the species in a broadly-circumscribed Lecidea rather than erecting a new monotypic genus. A key to saxicolous lecideoid lichens present on Atlantic coasts in Europe is also provided.

In this study we clarify the phylogeny and reassess the current taxonomy of the Micarea prasina group, focusing especially on the M. byssacea and M. micrococca complexes. The phylogeny was investigated using ITS, mtSSU and Mcm7 regions from 25 taxa belonging to the M. prasina group. A total of 107 new sequences were generated. Data were analyzed using maximum parsimony and maximum likelihood methods. The results reveal five undescribed well-supported lineages. Four of the lineages represent new species described as Micarea pseudomicrococca Launis & Myllys sp. nov., M. czarnotae Launis, van den Boom, Sérusiaux & Myllys sp. nov., M. microareolata Launis, Pykälä & Myllys sp. nov. and M. laeta Launis & Myllys sp. nov. In addition, a fifth lineage was revealed that requires further study. Micarea pseudomicrococca is characterized by an olive green granular thallus, small cream-white or brownish apothecia lacking the Sedifolia-grey pigment and two types of paraphyses up to 2 µm wide. Micarea czarnotae forms a granular, densely granular or continuous olive green thallus, convex to hemispherical apothecia often with the Sedifolia-grey pigment and no crystalline granules in the thallus. Micarea microareolata is characterized by a ± pale green areolate thallus (composed of goniocysts), cream-white apothecia lacking the Sedifolia-grey pigment and narrow spores. Micarea laeta has a vivid to olive green granular thallus, pale apothecia lacking the Sedifolia-grey pigment and wider spores compared to M. microareolata. Descriptions, images and a key are provided for the new species. Crystalline granules are introduced as a novel species-level character for Micarea.

Detailed morphological and anatomical studies informed by molecular inferences with mtSSU as a marker revealed two new species of Micarea in Western Europe, both belonging to the core group of the genus, namely the M. prasina group: M. herbarum from the Netherlands and Poland and M. meridionalis from Portugal and Italy. Micarea herbarum looks like a small or depauperate M. denigrata but clearly differs by the lack of gyrophoric acid, while M. meridionalis is distinguished by its granular thallus and the production of micareic acid.

Amandinea lobarica, a new corticolous lichen species, is described from high elevations in Guatemala. It is characterized by a thin, granulose, brownish thallus containing lobaric acid, small, convex lecideine apothecia, filiform conidia and large, narrowly ellipsoid ascospores with roughly ornamented walls. The new species is compared with other Buellia s. lat. taxa that possess rather large and strongly ornamented ascospores, such as Buellia hypothallina, here placed in synonymy with Gassicurtia vaccinii, Amandinea leucomela, A. mediospora, A. megaspora, A. subduplicata and five very closely related taxa treated here as belonging to the Amandinea incrustans group. Two tables summarizing the main differences between these species and a key are provided. New data on the chemistry of A. leucomela and a new record of A. montana for Guatemala are also included.

Detailed anatomical and chemical studies conducted on recent collections made in almost all suitable habitats on Réunion, a small remote tropical island in the Indian Ocean, yielded a surprising diversity in the widespread lichen genus Micarea (Pilocarpaceae, Lecanorales). Twenty-one species are recognized, including 13 described here as new to science. They are: Micarea alectorialica, M. bebourensis, M. borbonica, M. boryana, M. cilaoensis, M. hyalinoxanthonica, M. isidiosa, M. melanoprasina, M. pseudocoppinsii, M. pseudolignaria, M. sublithinella, M. takamakae and M. tenuispora. Notes on local ecology and important biogeographical features are also given and a key to the species is provided. Isidiiform areolae are reported for the first time in the genus (M. isidiosa and M. tenuispora), as well as the production of protolichesterinic and confluentic acids (M. sublithinella and M. takamakae, respectively). Two groups within the genus are species-rich on the island: the M. peliocarpa group with possibly 5 species, including 3 new to science, and the M. prasina group with 4 species, including 2 new to science. Micarea levicula is reported here for the first time since its description, and the status of the material that can be referred to M. micrococca s. lat. needs further study.

The new species Micarea usneae is described from Madeira. It has been found at two localities where it grew on epiphytic Usnea thalli. Micarea usneae is distinguished by a very thin pale brownish thallus, pallid to greyish black or bluish subglobose apothecia of 0·1–0·3 mm diameter, very narrow (1·5–2·5 µm) ascospores, black pycnidia and strongly curved to sigmoid macroconidia. Phylogenetic analyses using mtSSU sequences place the new species in the Micarea peliocarpa group. Catillaria usneicola and Cladonia parasitica are recorded for the first time from Madeira. A key to the lichenicolous species on Usnea in Macaronesia is provided.

Buellia subericola, a new corticolous species characterized by a brown, blastidiate thallus without secondary chemistry and triseptate to occasionally submuriform ascospores, is described from the southern Iberian Peninsula. The species occurs on Quercus suber in grass-woodlands of cork-oak in the mesomediterranean belt with a warm mediterranean climate and oceanic influence. It is compared with other known Buellia s. lat. taxa which also reproduce asexually and have similar ascospores.

Plectocarpon dirinariae Ertz & van den Boom is described from Cape Verde from the thallus of saxicolous Dirinariaapplanata. The new species is characterized by convex rounded ascomata not inducing basally constricted galls, non-carbonized sterile stromatic tissue, mainly 4–6-spored asci and 3-septate ascospores. Similar Plectocarpon sp. are discussed.

Lecania chlorotiza and L. falcata, described here as new from Spain/Navarra, the Canary Islands and the Azores, do not belong to Lecania s. str. They belong to a strongly supported clade comprising Bacidia, Bacidina, Scutula and Toninia when examined with maximum parsimony, maximum likelihood and Bayesian inferences using mtSSU, nuLSU and nuITS sequences. This clade represents the Bacidiaceae and is included in the Ramalinaceae s. lat. Most genera included in that family need further work before a new genus can possibly be described for Lecania chlorotiza and L. falcata.

Amandinea myrticola is described as new from Portugal. This corticolous species is characterized by the thin, smooth to minutely rugose and greyish thallus lacking secondary metabolites, the small lecideine apothecia which exhibit a pseudothalline margin when young and the small, smooth, Physconia-type ascospores with strongly pronounced and persistent median wall thickenings. It occurs on smooth bark in two localities characterized by a Mediterranean climate with an Atlantic influence.

Well-developed ascospores of Rinodina flavosoralifera have been observed for the first time. The ascospores are described and illustrated and new data on the chemistry and distribution of this species are provided. New chorological data on Rinodina disjuncta are also included.

Lecanographa uniseptata is described as new to science. It is characterized by having small rounded to lirellate ascomata, and 1-septate ascospores. The species is known from tropical Africa (Gabon) and tropical America (Guatemala).

A new lichen species, Waynea giraltiae van den Boom, is described from southern Portugal and Spain. It is characterized by a very fine tomentum on the squamulose thallus, fusiform, 3-septate ascospores, and strongly curved filiform conidia. It is the first species of the genus containing argopsin. The new species is compared with related Waynea species. Waynea cretica is recorded as new to the Iberian Peninsula.

Melanotopelia africana is described as new to science from Rwanda (continental Africa) and La Réunion (Mascarenes archipelago). Topeliopsis muscigena is here reported for the first time from La Réunion.

The silicicolous lichen species, Rinodina etayoi Giralt & van den Boom, is described as new from inland localities of Fuerteventura and Lanzarote (Canary Islands). It is characterized by a crustose, whitish thallus containing atranorin, zeorin, chloroatranorin and stictic acid, hemispheric pseudolecanorine apothecia containing, a proper exciple inspersed with numerous and large oil drops, and by ascospores of the Mischoblastia-type. The joint occurrence of pannarin, stictic acid and Mischoblastia-type ascospores makes R. etayoi unique within the genus.

Examination of Rinodina specimens from the Cape Verde Islands revealed three new species, which are described here: Rinodina capeverdeana Giralt & van den Boom, R. inspersoparietata Giralt & van den Boom and R. polymorphaespora Giralt & van den Boom. Additional information is given for six further species, of which five are new records for the archipelago. Rinodina punctosorediata Aptroot & Sparrius was found to be conspecific with R. stictica Sheard & Tønsberg.