The diversity of the Trypethelium eluteriae group in Thailand was studied using molecular (ITS and mtSSU rDNA sequences), morphological, and chemical data. Three species were recognized, T. eluteriae, T. platystomum, and T. subeluteriae, with the latter two being new records for Thailand. The separation of the three species, which have sometimes been regarded as synonymous, is supported by molecular and phenotypic characters. The chemical profiles of the three species are distinct, while ascospore size, often used to distinguish species in the group, shows some overlap.

Three new calicioid lichens are described from the Neotropics. Mazaediothecium uniseptatum, with 1-septate ascospores, is described from French Guiana. Mycocalicium enterographicola, with turbinate, green-pruinose apothecia and stalk and a distinct mazaedium, occurring lichenicolous on Enterographa cf. quassiaecola Fée, is described from Sergipe State in Brazil. Stenocybe tropica, with 3-septate ascospores remaining clustered in the mouth of the apothecium, and persistent asci, is described from mangrove tree bark in São Paulo State, Brazil.

The present treatment shows that the lichen family Trypetheliaceae is an important component of lowland and montane tropical forests in Bolivia. A total of 75 species are currently recognized in Bolivia, of which 24 are new to science and a further 37 are reported for the first time from the country. The following species are described: Architrypethelium penuriixanthum Flakus & Aptroot sp. nov. that differs from A. hyalinum in the lack of lichexanthone in the thallus; Astrothelium amylosporum Flakus & Aptroot sp. nov. that differs from A. subdisjunctum in having 8-spored asci and amyloid ascospores; A. bullatum Flakus & Aptroot sp. nov. that differs from A. megaspermum in having a bullate thallus, a clear hamathecium, 8-spored asci and smaller amyloid ascospores; A. carrascoense Flakus, Kukwa & Aptroot sp. nov. that differs from A. meristosporum in having broader ascospores without distinctly thickened median septa, an unidentified xanthone as major substance, and mostly eccentric ostioles; A. elixii Flakus & Aptroot sp. nov. that differs from all other Astrothelium species in the presence of lichexanthone in the outer layer of thallus and pseudostromata and isohypocrellin inside the pseudostromata, and muriform ascospores; A. inspersotuberculosum Flakus & Aptroot sp. nov. that differs from A. tuberculosum in having an inspersed hamathecium; A. megaeneum Flakus & Aptroot sp. nov. that differs from A. croceum in having a thallus covered by parietin, and mostly fused ascomata with intermediate, fused to separated ostioles surrounded by a common ostiolar area; A. neodiplocarpum Flakus, Kukwa & Aptroot sp. nov. that differs from A. diplocarpum in the absence of medullary pigment and in the amyloid ascospores; A. nigrocacuminum Flakus, Kukwa & Aptroot sp. nov. that differs from A. megochroleucum in having fused, eccentric ostioles and black (UV−) tops of the pseudostromata; A. pallidoflavum Flakus & Aptroot sp. nov. that differs from A. cinnamomeum in having wider ascospores; A. pyrenuliforme Flakus & Aptroot sp. nov. that differs from A. ecuadoriensis ecuadoriense in having shorter ascospores and in the presence of pseudocyphellae; A. subscoria Flakus & Aptroot sp. nov. that differs from A. scoria in having non-aggregated ascomata; A. variabile Flakus & Aptroot sp. nov. that differs from A. ochroleucoides in the longer ascospores; Bathelium boliviense Flakus & Aptroot sp. nov. that differs from B. lineare in the presence of isohypocrellin inside the pseudostromata; B. flavostiolatum Flakus & Aptroot sp. nov. that differs from all other Bathelium species in the presence of lichexanthone near the ostioles (tops of pseudostromata UV+ yellow) and an orange (K+ carmine red) pigment inside the pseudostromata, the absence of lichexanthone in the thallus, an inspersed hamathecium, and 13–17-septate ascospores; B. inspersomastoideum Flakus & Aptroot sp. nov. that differs from B. mastoideum in having an inspersed hamathecium; B. mirabile Flakus, Kukwa & Aptroot sp. nov. that differs from other Bathelium species in the pseudostromata containing isohypocrellin inside and parietin outside; B. pruinosum Flakus, Kukwa & Aptroot sp. nov. that differs from Astrothelium ochroleucoides in having 8-spored asci, shorter ascospores, an inspersed hamathecium, and an unidentified anthraquinone (orange pigment K+ carmine red) inside the pseudostromata; Constrictolumina chiquitana Flakus, Kukwa & Aptroot sp. nov. that differs from other known Constrictolumina species in having brown and 1-septate to submuriform ascospores; Dictyomeridium lueckingii Flakus & Aptroot sp. nov. that differs from D. proponens in having smaller and less septate ascospores; Polymeridium xanthoexcentricum Flakus & Aptroot sp. nov. that differs from P. alboflavescens in having mostly eccentric ostioles; Pseudopyrenula flavosuperans Flakus & Aptroot sp. nov. that differs from P. superans in having a hamathecium inspersed with yellow oil globules; Trypethelium astroideum Flakus & Aptroot sp. nov. that differs from T. subeluteriae in having K+ carmine red pseudostromata containing parietin inside and black tops with an additional unidentified anthraquinone (rust-red pigment K+ purple, UV−) on the outside, partly fused ostioles, and larger ascospores; and T. xanthoplatystomum Flakus & Aptroot sp. nov. that differs from T. platystomum in the presence of lichexanthone in the thallus.

Gneiss inselbergs in the Caatinga region of Ceará in equatorial Brazil are literally covered with a wide diversity of caloplacoid lichens. This includes two closely related new saxicolous species of Caloplaca, both with the aspect of a Lecanora of the subfusca-aggregate: C. lecanorocarpa has a grey areolate bullate thallus with atranorin on a black prothallus, grey thalline apothecium margin, sessile apothecia with glossy dark brown disc, and ascospores of 10–12×5·0–5·5 μm, with a 5·0–5·5 μm thick septum; and the similar, related C. lecapustulata which mainly differs by the rimose thallus with irregular mushroom-shaped pustules. The phylogenetic position of the two new species has been assessed to be within the Caloplacoideae. A key to all tropical lecanoroid Caloplaca species is provided.

In order to improve growth chamber protocols for lichens, we tested the effect of 1) wet filter paper versus self-drained nets as a substratum for lichens, and 2) gradual versus abrupt transitions between dark and light periods. For Lobaria pulmonaria (L.) Hoffm. cultivated on nets, RGR increased by 60% compared to those on wet papers, whereas abrupt on/off transitions between day/night gave as high growth rates as gradual transitions mimicking sunrise/sunset. Because thalli on nets had less surface water than those on papers, the higher RGR on nets likely resulted from less suprasaturation depression of photosynthesis. By supporting very high growth and eliminating any visible damage, the revised growth chamber protocols facilitate new functional lichen studies.

Lecanora inaurata, a corticolous member of the L. subfusca group, is described as new to science. This species is characterized by typically epruinose, reddish brown apothecial discs, a chlarotera-type epihymenium, pulicaris-type amphithecium, and chloroatranorin and zeorin as major constituents, often with accessory calycin in the thalline margins of the apothecia, imparting a distinctive yellow halo appearance when present in sufficient concentrations. Lecanora inaurata occurs in open hardwood-dominated woodlands of the Edwards Plateau and grasslands of the southern Great Plains in Oklahoma and Texas.

Cladonia is one of the largest lichen-forming ascomycete genera. It was formerly divided into ten sections, three of which, Crustaceae (Cladina), Tenues, and Impexae, are called the reindeer lichens. While previous studies have elucidated the relationships between species and sections, they often examined only one or a few specimens of each species in the analysis. This study examined the monophyly of selected members of sections Crustaceae, Tenues, and Impexae and their relationships in the genus Cladonia using the internal transcribed spacer region of the nuclear ribosomal DNA (ITS rDNA) and the mitochondrial small subunit gene of the mitochondrial ribosomal DNA (mtSSU). The phylogenetic tree contained four clades, two representing species in section Impexae, one representing species that belong to sections Crustaceae and Tenues, and one clade with C. arbuscula and related species. Five of 22 species, C. pycnoclada, C. stellaris, C. evansii, C. ciliata and C. subtenuis, showed monophyly in the phylogenetic tree; some of these 5 species have been shown previously to be monophyletic. The thallus branching pattern was interpreted as an important heritable character using the mtSSU network. Three duplets of paraphyletic species were further examined using ITS rDNA haplotype networks and AMOVA analysis. The results for the species duplets showed some mixing of haplotypes but the AMOVA analysis provided support for species separation within the duplets. While the evidence supports distinct species, further study is needed to conclusively show separate species in these duplets.

The foliose lichens Pseudocyphellaria pilosella and P. piloselloides are characterized by a cyanobacterial photobiont, a tomentose upper surface, a yellow medulla and yellow pseudocyphellae. The latter species has long been recognized as the sorediate counterpart of the former. The morphological, anatomical, chemical, and molecular analyses performed for this study support their treatment as a single species.

Sulzbacheromyces is a recently erected genus in Lepidostromatales, differing from Lepidostroma in the crustose thallus. After the initial discovery of S. caatingae, the only species to be found in Brazil so far, a large quantity of additional data and ITS barcoding sequences for this taxon from a much broader geographical range and different habitats was collected. Phylogenetic analysis under a maximum likelihood framework demonstrated that all specimens are genetically uniform, showing no variation in their ITS, suggesting that S. caatingae has a wide ecological amplitude beyond the Brazilian Caatinga and Atlantic Forest biomes. Detailed descriptions and illustrations of the species are presented, including a map showing the distribution of S. caatingae in the Brazilian semi-arid region and the north-eastern Atlantic rainforest.

The following 24 new species of Trypetheliaceae are described after three weeks of fieldwork in an area with a radius of 50 km around Porto Velho in Rondônia: Astrothelium bivelum with astrothelioid ascomata, 5-septate ascospores with polar gelatinous caps, and a thallus without lichexanthone; A. curvisporum with bent, 5-septate ascospores of 115–135×29–36 μm with a 17–22 μm thick gelatinous layer; A. decemseptatum with pseudostroma that are essentially black and look like breaking through the bark, with anthraquinones mostly on the pseudostromata but also on some parts of the thallus, best seen under UV light as the colour of the pruina is not very strong, and ascospores (7–)9–11-septate, fusiform, 50–65×11–17 μm; A. disjunctum with black pseudostroma and ascospores 3-septate, (27–)29–33×(8–)12–14 μm; A. duplicatum which is similar to A. mesoduplex, but pseudostroma are only yellowish inside and ascospores 45–55×11–15 μm; A. eumultiseptatum which is similar to A. eustomum, but with 9–11-septate ascospores of 65–70×15–17 μm; A. eustomurale which is also similar to A. eustomum, but with submuriform ascospores of 37–45×15–19 μm; A. flavoduplex which is similar to A. mesoduplex, but with ascospores 110–350×20–27 μm and the thallus containing lichexanthone; A. flavomurisporum with deeply immersed ascomata with muriform ascospores of 165–200×28–35 μm, with a distinctly thickened central septum and yellow oil; A. flavostromatum which is close to A. aeneoides and mainly differs by the bullate thallus and the cream pseudostromata; A. flavum which is similar to A. aeneum, but differs in the contrast between the linear to reticulate yellow stromata and the unpigmented thallus, and the ascospores of 16–18×6–7 μm; A. mesoduplex which is similar to A. flavoduplex, but with ascospores 90–100×20–23 μm and a thallus without lichexanthone; A. nigrum with mostly conical black pseudostromata that contrast sharply with the thallus, superficially resembling Pyrenula infraleucotrypa; A. novemseptatum which is similar to A. eumultiseptatum, but without lichexanthone anywhere in the thallus or pseudostroma; A. ochroleucoides which is similar to A. corallinum, but with lichexanthone on the thallus and pseudostromata; A. octoseptatum which is similar to A. eumultiseptatum, but with the whole pseudostroma, not just the ostioles, containing lichexanthone, and ascospores somewhat asymmetrical, which is highlighted by the unusual dominant even number of septa (eight) and the asymmetrically placed central septum in the case of uneven septum numbers; A. quatuorseptatum which is similar to A. octoseptatum Aptroot & M. Cáceres, but without lichexanthone, ascospores somewhat asymmetrical, which is highlighted by the unusual dominant even number of septa (four) and the asymmetrically placed central septum in the case of uneven septum numbers; A. robustosporum with solitary ascomata with an eccentric ostiole, and ascospores 11–15-septate, 90–125×20–27 μm; A. solitarium which is similar to A. ceratinum (Fée) Aptroot & Lücking, but with ascospores 33–36×10–11 μm; A. stromatofluorescens which is close to A. phlyctaena, but with lichexanthone only on the pseudostroma, not on the thallus; A. supraclandestinum is close to A. subclandestinum, but the hamathecium is not inspersed; A. testudineum with solitary ascomata with an eccentric ostiole, an inspersed hamathecium, and ascospores 8 per ascus, muriform, 50–65×23–27 μm; A. xanthosuperbum which is similar to A. disjunctum, but with muriform ascospores, 130–160×28–35 μm; and Pseudopyrenula flavoreagens which is similar to P. subgregaria, but with lichexanthone in the thallus. Only a few species were also found elsewhere, such as other areas of Brazil, or in Venezuela, Colombia, Guyana, Panama, Australia and/or Papua New Guinea. Currently, 55 species of Trypetheliaceae are known from this spot, including 46 species of Astrothelium. The Amazon basin is the centre of diversity for the family, at least for Astrothelium, the largest genus in the family.

The following 16 new species of Trypetheliaceae are described from Brazil: Astrothelium aeneoides Aptroot, differing from A. aeneum by the absence of pigment on the thallus, but medulla of pseudostroma K+ blood red and ascospores 3-septate, lumina diamond-shaped; A. curvatum Aptroot & M. Cáceres with immersed pyriform ascomata with lateral ostioles and bent, muriform ascospores, 74–90×25–34 μm; A. globosum Aptroot & M. Cáceres with immersed ascomata, thallus consisting of nearly globose warts and ascospores 3-septate, 35–40×11–13 μm; A. graphicum Aptroot & S. M. A. Martins with an extended, reticulate pseudostroma, which is lower than the slightly bullate thallus, orange pruina on the thallus and pseudostroma and ascospores muriform, 60–66×12–16 µm; A. longisporum Aptroot, J. R. Silva & M. Cáceres, which differs from A. megaspermum by the eccentric ostioles and the 8 instead of 4 ascospores per ascus; A. macrostomum Aptroot which is similar to A. eustomum (Mont.) Müll. Arg., but differing by the 5–7-septate ascospores 65–85×16–19 μm.; A. megeustomum Aptroot & Fraga Júnior which is similar to Astrothelium eustomum, but with muriform ascospores 117–125×17–21 μm; A. pictum Aptroot with 5-septate ascospores, red crystals in the pseudostroma medulla and lichexanthone in the thallus; A. rubrocrystallinum Aptroot & M. Cáceres which is similar to A. annulare, but with copious red crystals in a thick layer around the ascomata and ascospores 22–27×7–9 μm; A. simplex Aptroot & S. M. A. Martins with 3-septate ascospores and a very rough thallus, differing from A. sinuosum by the lack of lichexanthone; A. sinuosum Aptroot & Gumboski with an ostiolar UV+ yellow reaction, bullate thallus and a wavy gelatinous sheath around the ascospores; A. tetrasporum Aptroot & M. Cáceres which is similar to A. puiggarii, but differs by the non-inspersed hamathecium and the ascus that contains only 4 ascospores; Polymeridium endoflavens Aptroot, D. S. Andrade & M. Cáceres with yellow oil inspersion in the hamathecium and 5–7-septate ascospores 32–37×10–13 μm; P. longiflavens Aptroot, Mendonça & M. Cáceres with yellow oil inspersion in the hamathecium, an apical ostiole and 9–11-septate ascospores 57–70×12–14 μm; Trypethelium luteolucidum Aptroot, Mendonça & M. Cáceres which is similar to T. regnellii, but differs by the presence of anthraquinone crystals in the pseudostromata; and Viridothelium leptoseptatum Aptroot & M. Cáceres, resembling Astrothelium aeneum but with no pigment on the thallus, a thin to absent thallus cover on the ascomata and thin-walled, constricted ascospores with lumina of a similar shape to the ascospore cell walls. Most are known only from Brazil, but a few are also known from Mexico, Puerto Rico, and/or Guyana. North-eastern Brazil is the centre of diversity of the genus Polymeridium, with 33 species now known.

Tyrosinases are a widespread family of multicopper oxidase enzymes. In our earlier work, we identified the presence of tyrosinases in lichenized Ascomycetes based on their substratum specificity, sensitivity to inhibitors and molecular mass. Here, we present a more detailed characterization of a tyrosinase from the lichen Lobaria pulmonaria. We also compare tyrosinase activity with the activities of laccases and peroxidases, the other redox enzymes present in this species. The importance of tyrosinases in lichen biology was studied by testing their role in melanin synthesis. Laboratory experiments clearly showed that tyrosinases from L. pulmonaria resemble those from other lichens and in free-living fungi. While the tyrosinases can metabolize the melanin precursor L-DOPA, L-DOPA can also be metabolized by peroxidases and laccases. A field experiment showed that exposing shade-adapted L. pulmonaria to normal solar radiation induces L-DOPA melanin synthesis. Synthesis occurred when lichens were exposed to either direct sunlight, or placed under a wavelength-neutral filter that slightly reduced overall light. In lichens receiving unfiltered sunlight, melanin synthesis was accompanied by increased laccase activity; by contrast, no changes in enzyme activity occurred in lichens placed under the wavelength-neutral filter. Melanization was reduced by placing lichens under filters that removed UV-B, and prevented by filters that removed both UV-A and UV-B. Removing UV-B had no effect on enzyme activity, whereas removing both UV-A and UV-B increased tyrosinase activity. Results from this study indicate that under some conditions laccases may be involved in melanin synthesis, but they provide no evidence for a role for tyrosinases in melanization. Although high tyrosinase activities are widespread in lichens, many questions on the role of this enzyme in lichen biology remain to be answered.

The aim of this study was to evaluate the spatial effect of a natural source of sulphur pollution on the species diversity, richness and distribution of corticolous lichens in a páramo zone at the mine ‘El Vinagre’ (Puracé, Cauca, Colombia). Three zones at different distances from the pollution source were established: zone 1 with a high degree of contamination, a potentially mildly affected or transitional zone 2, and a zone 3 free of disturbance. In each zone, 10 phorophytes of Weinmannia microphylla (Cunoniaceae) were sampled, and all lichens in a 150 cm vertical transect 50 cm above the ground were collected and identified. Phorophyte parameters were measured (bark pH and diameter at breast height) and the samples were georeferenced. In order to evaluate the impact on lichens, non-metric multidimensional scaling (NMS) and indicator species analysis were carried out. ANOVA and Spearman correlations were performed to assess the relationships of environmental and tree variables between zones and with lichen community structure. The index of atmospheric purity (IAP) and the environmental rating factor (FCA) were evaluated for the three zones. In total, 104 lichen species were recorded, of which 72 were identified to species, 17 to genus, and four to family; 11 samples could not be identified. NMS clustered samples according to zone and the main axis which were correlated with bark pH and distance from pollution source. We found eight indicator species characterizing different zones, and four marginally significant indicator species. Using the IAP, we established three isocontamination areas, with zones 2 and 3 classified as more or less pristine zones and zone 1 as a polluted zone (supported by bark pH as a proxy for current pollution). Diversity was lowest in zone 1, closest to the pollution source, and lichen species composition differed between zones. Differences between lichens in zones 2 and 3 appear mostly unrelated to the current pollution source and might be more related to historical differences in impact from a 20-year-old pollution source.

A revision of the North American members of the Leptogium saturninum group (i.e. species with long lower-surface hairs, isidia, and usually smooth upper surface) is presented based on molecular phylogenetic analyses of mtSSU and nrITS sequence data, together with an extensive morphological study. Three species supported by both molecular and morphological characteristics are recognized: L. acadiense sp. nov. (distinguished by granular saturninum-type isidia, medulla composed of irregularly arranged or perpendicular hyphae), L. cookii sp. nov. (distinguished by cylindrical saturninum-type isidia) and L. hirsutum (distinguished by hirsutum-type isidia and medulla composed of loosely intertwined hyphae). One species supported by morphological characteristics, but for which no molecular data could be generated, is also recognized: L. compactum sp. nov. (distinguished by hirsutum-type isidia and medulla composed of tightly packed hyphae). Finally, L. saturninum (distinguished by granular saturninum-type isidia and medulla composed of perpendicular and parallel hyphae) is supported by morphological characteristics but molecular data from geographically diverse populations, including those near the type locality, indicate that the morphologically defined species is paraphyletic. Leptogium burnetiae is excluded from North American based on morphological study of the type. The species are described and illustrated in detail, and are distinguished morphologically by their isidium development, morphology of mature isidia, and pattern of hyphae in the medulla in transverse sections near lobe margins. A key to the members of the L. saturninum group and related species is also presented.

Usnea is a cosmopolitan genus of lichen-forming Ascomycota (Parmeliaceae, Lecanorales). This hyperdiverse genus remains poorly known, especially in tropical regions, and recent efforts have been made to clarify the species concepts and describe the diversity of species. We describe five new species from tropical South America based on morphological and chemical features supported by molecular data from the ITS rDNA, nuLSU, RPB1 and Mcm7 markers. Usnea clerciana is a Galapagos endemic characterized by inflated branches holding elongated tubercles, excavate soralia and/or apothecia. Usnea aranea and U. subaranea share inflated branches with numerous papillae and a loose arachnoid medulla, but differ in the minute and irregular soralia in U. aranea, that are circular and excavate in U. subaranea. Usnea rubriglabrata and U. subglabrata are characterized by inflated branches with excavate soralia, with a reddish cortex pigmentation in U. rubriglabrata that is lacking in U. subglabrata. Usnea aranea, U. rubriglabrata, U. subaranea and U. subglabrata are so far endemic to continental South America; the three former species are closely related and cluster in a highly supported clade, characterized by species distributed in the tropical Andes. New records for the region are provided and U. moreliana is resurrected, corresponding to the valid name for U. rubricornuta.

Porpidia hypostictica is described as a new species; it has a white to grey-white thallus with yellow, oxidized patches near the margin, and contains hypostictic acid as the only major compound. A phylogenetic analysis is provided which is based on ITS sequences using ML and Bayesian analyses. The phylogeny supported the separation of the new species from other species. A key to all known Chinese Porpidia species is provided.

The composition of fatty acids (FAs) is known to discriminate families within genera of bacteria, fungi, octocorals and algae. Here, we applied the more sensitive gas chromatographic (GC) analysis to investigate the taxonomic value of using FA composition to discriminate 15 species of lichen, including three chlorolichens (two Cladonia species and Stereocaulon scutelligerum), nine tripartite lichens (Stereocaulon species) and three cyanolichens (Lichina pygmaea, Collema cristatum, Peltigera membranacea). One macroscopic cyanobacterium (Nostoc sp.), corresponding to the photobiont partner of Peltigera and Collema cyanolichens, was included for comparison. Five lipid extraction methods were evaluated, using Stereocaulon scutelligerum. Shaking at 80 °C with chloroform/methanol (2:1, v/v) was the most efficient and reproducible method. The total FA composition of the 16 species was compared, using GC coupled with flame ionization detection or mass spectrometry. A statistical hierarchical cluster analysis was used to determine the similarity between the FA profiles, based on total, saturated, unsaturated and branched-chain FAs (BCFAs). The BCFA profile allowed a distinction between the Stereocaulon species and the cyanolichens, in contrast to all the other types of FAs. A detailed characterization of eight FA subclasses, provided by the GC analysis, suggested a preferential pathway for the biogenesis of unsaturated FAs through desaturases, which was especially favoured in the cyanolichens.

Five new species and one new record of Astrothelium (Trypetheliaceae) are reported from Thailand. Phylogenetic analysis of four DNA loci (ITS, nuLSU, mtSSU rDNA and RPB1) demonstrated the placement of the new species within Astrothelium, as well as their distinction from similar or related taxa. The new species are: A. flavocoronatum, with a yellow pigment surrounding the ostiole, and 3-septate ascospores 22–28×8·0–9·5 µm; A. macrostiolatum, with large whitish ostiolar area, a hamathecium inspersed with small oil droplets, and 9–11-septate ascospores 80–100×17–19 µm; A. neglectum, with lichexanthone on the thallus and pseudostromata, a non-inspersed hamathecium and 3–5-septate ascospores 21–25×7·5–9·5 µm; A. neovariolosum, with inspersed hamathecium and 3-septate ascospores 17–23×6–7 µm; and A. siamense, with inspersed hamathecium and 4–7-septate ascospores 30–50×10·5–12·0 µm. Astrothelium aenascens is reported from Thailand for the first time.

Western North America is the global centre of diversity for Letharia, a distinctive and cryptically diverse genus of lichenized fungi belonging to the Parmeliaceae. The genus is characterized by a shrubby, fruticose habit and presence of vulpinic acid. Previous studies using multiple fungal nuclear loci revealed the existence of two distinct species-level lineages within the traditional concept of L. vulpina and four such lineages within L. columbiana. Here we use molecular sequence data in an attempt to settle long-standing taxonomic issues in the genus. Our results confirm the widespread existence within L. vulpina s. lat. of two distinct species-level groups, each forming a mutually exclusive partnership with a separate algal clade within Trebouxia jamesii s. lat. Accordingly, we formally describe the segregate species L. lupina sp. nov. Our results also support the evolutionary independence of four candidate species previously circumscribed from L. columbiana s. lat. One of these lineages, L. ‘gracilis’, has already received species recognition as L. gracilis, while a second, L. ‘lucida’, is epitypified here against L. columbiana s. str. Based on results from species delimitation analyses under the multispecies coalescent model, the two remaining lineages, L. ‘barbata’ and L. ‘rugosa’, also warrant formal taxonomic recognition; however, we refrain from describing these species pending additional studies of diagnostic characters, ecological preference, and distributions.