Two new species of the lichenized genus Lasioloma are described from Asia: Lasioloma longiramosum W. C. Wang & A. Abas (collected from Malaysia), is characterized by a distinct woolly prothallus between dispersed thallus patches, comparatively small, muriform ascospores, long filiform conidia (main branch 22–28 μm in length, the other three branches 65–80 μm) and a foliicolous habitat; L. verrucosum W. C. Wang & X. L. Wei (collected from China), is characterized by a warted thallus, filiform conidia (main branch 22–32 μm in length, the other three branches 50–65 μm) and a corticolous habitat. The placement of both new species was confirmed by a molecular phylogenetic approach based on combined ITS, mtSSU and mtLSU sequences, and both are compared in detail to other similar species of the genus. Our study also revealed that the length of the conidial branches, which has not been explored in previous studies, should be regarded as an important feature for species delimitation in Lasioloma.

The tropical areas of eastern Asia contain a high diversity of foliicolous lichens, including various species of the genus Badimia. Badimia xanthocampylidia W. C. Wang & J. C. Wei is described from tropical rainforests in southern China and Thailand based on morphology, chemistry, and combined mtSSU, ITS and nrLSU sequences. It is characterized by a pale green thallus with yellow verrucae and bright yellow campylidia and the presence of isousnic acid. Three other species, B. multiseptata Papong & Lücking, B. pallidula (Kremp.) Vězda and B. polillensis (Vain.) Vězda, are discussed and the genus Badimia is newly reported from China. A worldwide key to currently known species in the genus is presented.

The phylogeny of foliicolous taxa in Pilocarpaceae was reconstructed using Bayesian and maximum likelihood analyses of concatenated ITS and mtSSU sequences. Sixty-six new partial sequences representing 36 taxa were generated and 29 sequences were downloaded from GenBank. Our results indicate that Lasioloma R. Sant. is nested within a paraphyletic Calopadia Vězda, whereas Fellhanera Vězda is polyphyletic and the phylogenetic relationships of Eugeniella Lücking et al. and Sporopodium Mont. with Fellhanera require further investigation. In addition, Tapellaria parvimuriformis W. C. Wang & J. C. Wei is described as a new species from Khao Yai National Park, Thailand, and is characterized by its small muriform ascospores, grey campylidia with a pale base, and short conidia. Eight new records of foliicolous lichens for Thailand are also listed.

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.

Foliicolous lichens complete their life cycles upon non-deciduous leaves in humid tropical and subtropical environments. The anatomy of these lichens and its adaptations to this specialized niche have received only limited attention. The present work examines the structural organization in seven species of the Gomphillaceae that colonize palm leaves in south-west Florida, USA. Thalli with their leaf substratum were embedded in resin and examined with SEM in backscattered electron detection mode. All species showed a continuous, covering epilayer of fungal origin that consisted of relatively sparse, scattered cell lumina of reduced diameter connected by cell wall-derived material. Fungal cells were intermixed below this layer, with algal cells often resting directly on the substratum. Interactions between symbionts were mainly limited to wall-to-wall contacts without penetration. The epilayer showed continuity with the fungal prothallus at the perimeter of the thalli. Crystalline deposits in the upper portions of thalli were common, particularly in the species of Gyalectidium examined. All thalli were entirely epicuticular; some covered the stomata of the leaf beneath. It is suggested that the prominence of non-living wall materials and mineral crystals in thallus structure might serve to minimize the metabolic cost of fungal tissue in climates where warm temperatures at night result in higher rates of respiration.

The foliicolous lichenized fungus Calopadia erythrocephala Farkas, Elix & Flakus, is described as new to science from the Atlantic submontane rainforests in Brazil. The species is very similar to C. puiggarii, but is distinguished by the presence of a red pigment in the campylidia, the darker apothecial discs and larger conidia. Fusarubin, the red pigment produced by the new species, is reported for the first time from foliicolous lichens. A world-wide key to foliicolous species of Calopadia with single, muriform ascospores is presented.

Six new species of foliicolous lichenized fungi are described as new to science from Bolivian lowland Amazon forest: Asterothyrium vezdae Flakus & Lücking (Asterothyriaceae), Keratosphaera multiseptata Flakus & Lücking (Pseudoperisporiaceae), Phylloblastia bielczykiae Flakus & Lücking (Verrucariaceae), Porina boliviana Flakus & Lücking (Porinaceae), Tapellaria intermedia Flakus & Lücking (Pilocarpaceae) and Trichothelium subargenteum Flakus & Lücking (Porinaceae). In addition, new records of 70 lichen species in Bolivia are listed. Of these, 52 are new to Bolivia.

One new species and 71 new records are reported from Thailand. Coenogonium disciforme sp. nov. is distinguished by its disc-shaped, shortly stipitate isidia, which leave perfectly circular holes, almost like punched holes, when detached.

Revision of world-wide material of Cryptothecia candida sensu Santesson (1952) revealed that three different species are involved, differing in the shape of their ascomata, chemistry, and distribution. C. candida (Kremp.) R. Sant. s. str. [syn.: Arthonia lacerata Vain.; C. epiphylla R. Sant.] contains 2′-O-methylperlatolic acid and 2′-O-methylanziaic acid (thallus and ascomata C+ red) and has rounded to slightly irregular ascomata; it is a paleotropical species occurring in Africa and SE Asia (absent in Australia). All neotropical populations previously identified as C. candida contain perlatolic acid (thallus and ascomata C−) and are further characterized by their well-delimited, regularly rounded ascomata. The name Cryptothecia filicina (Ellis & Everh.) Lücking & G. Thor comb. nov. [bas.: Ascomycetella filicina Ellis & Everh.; syn.: Myxotheca hypocreoides Ferd. & Winge] is taken up for this taxon. A third species was discovered in material from Australia and China (Hong Kong) and is here described as Cryptothecia irregularis Lücking, Aptroot, Kalb & Elix sp. nov. Its ascomata are radiately elongate and it contains psoromic, subpsoromic, 2′-O-demethylpsoromic, and confluentic acids.

The foliicolous lichens and the environmental factors at 14 stations in Catalonia were examined and the relationships between their foliicolous flora and climatic features analysed. This information could be used to predict potential sites with foliicolous lichens in areas with a Mediterranean climate. In addition, two species new to the European lichen flora (Bacidina canariensis and Fellhanera semecarpi) are recorded, and also 8 species new to the lichen and lichenicolous flora of the Iberian Peninsula (Arthonia leptosperma, Byssoloma diederichii, Chionosphaera apobasidialis, Cladosporium arthoniae, Fellhanera christiansenii, Fellhanera seroexspectata, Strigula smaragdula and Vezdaea dawsoniae).

The utility of plastic cover slips as a substratum for in situ study of lichen developmental stages is further explored in a neotropical foliicolous lichen community and in a European temperate corticolous community. Twenty-one months after placement in the tropical forest, the cover slips bore foliicolous lichen thalli with several species producing characteristic ascocarps and ascospores, indicating the suitability of the substratum for completion of the life cycle of these lichens. On cover slips placed within the temperate corticolous community, lichen propagules anchored to the substratum with relatively short attachment hyphae but did not develop further within the one year observation period. Intimately intermixed microbial communities of short-celled, mainly pigmented fungi and chlorophyte algae developed upon the transparent substratum. Among the algae, Trebouxia cells, often in groups showing cell division and without associated lichenizing hyphae, were commonly observed. The potential significance of the free-living populations in the life cycle of Trebouxia and in those of Trebouxia-associated lichen fungi is discussed.

An inventory of foliicolous lichens in Mexican lowland and montane rainforest revealed a total of 288 species, 238 of which are new records for the country, raising the number of reported lichen species to c. 1800. Among the new records, there are 29 recently described species and four new records for the Neotropics and the Americas, while five taxa are for the first time reported for Central America. The 293 species now known from Mexico comprise nearly two-thirds pantropical to cosmopolitan or intercontinentally distributed taxa, whereas little more than one-third are Neotropical or American, and only 6% are potentially endemic to the country. A comparison with other lowland and montane rainforest sites in Guatemala, Costa Rica and Ecuador shows that on average lowland sites have twice as many species as montane sites. Also, the differentiation in species composition between lowland and montane sites within the same region is more pronounced (63–75% similarity) than that between adjacent regions (96–99% similarity for lowland sites and 83–87% similarity for montane sites). This means that altitudinal preferences affect species composition more strongly than geographical differentiation. The latter is a function of distance, however, while Mexican and Guatemalan lowland (montane) sites share 96% (83%) of the species, these values drop to 74% (72%) when comparing Mexico with Ecuador. Nevertheless, overall floristic similarity is very high, with the lowest value of 54% shared species found between Mexican lowland and Costa Rican montane forest.

Nine new species of foliicolous lichens are described from Los Tuxtlas Tropical Biology Station, Veracruz, Mexico: Asterothyrium atromarginatum sp. nov. (Asterothyriaceae), Enterographa perez-higaredae sp. nov. (Roccellaceae), Gyalectidium barbatum sp. nov., G. pallidum sp. nov., G. ulloae sp. nov. (Gomphillaceae), Opegrapha heliabravoa sp. nov., O. tuxtlensis sp. nov. (Roccellaceae), Pocsia alvari sp. nov. (Verrucariaceae) and Tricharia sublancicarpa sp. nov. (Gomphillaceae). Pycnidia are reported for the first time in Coenogonium hypophyllum (Vězda) Kalb & Lücking.

The first FT-Raman spectroscopic study of foliicolous lichens is reported. Detailed spectra obtained by macroscopic and microscopic means for Calenia triseptata Zahlbr., Echinoplaca strigulacea (Müll. Arg.) R.Sant. and Tricharia carnea (Müll. Arg.) R.Sant. collected from Costa Rican rainforests have been interpreted mainly in terms of their xalate content. The Raman spectra show a significant presence of calcium oxalate monohydrate (whewellite) despite the lack of calcium ions available in the leaf itself. A reasonable explanation for its presence could be the result of the incorporation of calcium ions from airborne dust and/or dissolved in rain falling on the canopy.