An investigation of the genus Usnea, in the biodiversity hotspot of the Republic of São Tomé and Príncipe in tropical West Africa, is presented here. Fifteen species, or species aggregates, were recorded for the islands: Usnea articulata aggr., Usnea baileyi (Stirt.) Zahlbr., Usnea beckeri P. Clerc & Nadel, Usnea bicolorata Motyka, Usnea erinacea aggr., Usnea exasperata (Müll. Arg.) Motyka, Usnea firmula (Stirt.) Motyka, Usnea krogiana P. Clerc, Usnea longiciliata P. Clerc & Nadel, Usnea nodulosa Swinscow & Krog, Usnea pectinata aggr., Usnea sorediosula Motyka, Usnea submollis J. Steiner, and two undetermined species. Two species of lichen are described as new to science: U. beckeri and U. longiciliata. Both species are characterized by a dense and brittle, dark green thallus, the presence of apothecia surrounded by long cilia-like fibrils, a lack of soredia, and the presence of two unknown substances; however, whereas U. beckeri has a pendant growth form and can reach 25 cm in length, U. longiciliata is differentiated by a shrubby growth form of less than 6 cm. These two species also have different ascospore dimensions. A molecular phylogenetic analysis is presented that lends support to their description as new species. Additionally, Usnea krogiana is noted as new to continental Africa and nine Usnea species or aggregates are noted as new to the Islands of São Tomé and Príncipe in the Gulf of Guinea.

Bryona tortuosa is reported as new to northern Europe. Notes on its morphology, chemistry, ecology and distribution are given and the distinction from its closest ally, B. fremontii, is discussed.

The production of anthraquinones is a major characteristic of most species in the Teloschistaceae. Other secondary metabolites are quite rare in this family, but some species are known to produce depsides, depsidones, xanthones and usnic acid. A new monotypic genus, Neoplaca, with a new species N. mirabilis, is described from the subfamily Caloplacoideae of the family Teloschistaceae, lacking anthraquinones but containing the naphthopyrans simonyellin and consimonyellin. This is the first time this class of organic compounds has been found in the family Teloschistaceae and the second in the order Teloschistales, where simonyellin has been detected in Brigantiaeaceae. Simonyellin and consimonyellin have also previously been reported in the family Roccellaceae. Neoplaca mirabilis is currently known from the two nearby localities in Yakutia, Russia, where it is common and grows on base-rich soil on exposed south-facing siliceous outcrops. The thallus consists of scattered whitish to greyish, or rarely with pale yellow tinge, squamules 1–4.5 mm diam. and 0.3–1 mm thick with citrine to orange-yellow blastidia produced from their margin; apothecia and pycnidia are unknown. In addition to naphthopyrans, N. mirabilis contains an unidentified brown pigment similar in some features to melanin. The new species is also interesting in that the pigments are apparently located inside the cells of the cortex, not on their surface, where anthraquinones are found in Teloschistaceae.

Recent studies have demonstrated that species boundaries among the lichen-forming fungi are in need of revision with the discovery of cryptic species in numerous clades, especially in parmelioid lichens. Here we focus on addressing the species boundaries in Canoparmelia texana, a sorediate species with a pantropical distribution that extends into temperate regions. We extracted DNA sequences of the nuclear ribosomal internal transcribed spacer region (ITS), large subunit (nuLSU) and mitochondrial small subunit (mtSSU) from samples mostly collected in Kenya, and analyzed them in a phylogenetic framework. We illustrate that our samples of the species as currently circumscribed do not form a monophyletic group but fall into two distinct clades, with the apotheciate C. nairobiensis nested within. Both of the discovered lineages have a wide distributional range and are common in Kenya, and Parmelia albaniensis C. W. Dodge is resurrected to accommodate one of the clades; consequently a new combination, Canoparmelia albaniensis (C. W. Dodge) Divakar & Kirika comb. nov., is proposed.

Dirina mexicana Tehler from the western coasts of Mexico is proposed as a new species. It mostly resembles D. immersa and D. insulana from the western mediterranean region in Europe.

RNase activity in Lasallia hispanica, Parmelia omphalodes and Cornicularia normoerica collected at different times and in different habitats, have shown variability that cannot be solely attributable to variation in habitat or season. Electromorph pattern of RNase activity in L. hispanica and C. normoerica, showed variations among different collection times; some bands are constant but other showed high variability, which could be related to physiological changes. It is also noteworthy that in both species one band is exclusively present in thalli from one of the sampling localities. This could be the result of an adaptation to this habitat and/or due to genetic differences.

The new species Lichinella japonica Harada & Henssen is described for the first time from Japan. L. japonica differs from known species in thallus structure and ecology. It is the first record of the genus from East Asia.

Thallus organization is examined in Aspicilia californica Rosentreter, fruticose lichen known from several localities in central and southern California. The sprawling, terete thallus branches possess a dense central medulla of thickwalled, longitudinally oriented fungal cells. This central tissue emerges at branch apices to form a darkly pigmented fungal tip. Thallus development involves the apical extension of the tip to produce a fungal tissue over which a cylindrical algal layer and cortex will eventually be formed. Apical branches are initiated by furcation entirely within the fungal tip. Lateral branches, emerging from the lichenized thallus, arise as a divergent bundle of elongate fungal cells originating in the medulla. The photobiont appears to play no direct role in initiation of apical or lateral branches. It is concluded that thallus development in A. californica occurs with a relatively low degree of synchrony between mycobiont and photobiont growth, similar to the pattern observed in crustose lichens with prothallic growth. A rather similar type of thallus organization is observed in A. hispida, although in that species mycobiont growth and branch initiation appear to be somewhat more closely associated with algal cell proliferation. A squamulose Aspicilia from central Spain produces rhizomorphs that may sometimes become invested with an algal layer and cortex, resembling the thallus axes of A. californica.