Two new species of Bryoria are described based on morphology, chemistry and molecular phylogeny (ITS and Mcm7). Both species belong in section Bryoria, which was resolved as a polyphyletic group in the ITS+Mcm7 phylogeny. Bryoria alaskana belongs to a clade restricted to South-East Asia and north-west North America, and is so far known from south-east Alaska and the Sino-Himalayan Mountains. This highly variable species is most reliably recognized by its pendent, esorediate thallus, its production of fumarprotocetraric acid, and the combination of isotomic branching, abundant, whitish, predominantly fusiform pseudocyphellae, and sparse, short perpendicular side branches. Black emorient patches are lacking. Bryoria irwinii is endemic to north-west North America and is closely related to B. araucana from South America, B. poeltii from South-East Asia, as well as B. nadvornikiana and B. trichodes, both widely distributed in the Northern Hemisphere. It is a subpendent, esorediate species recognized by its predominantly anisotomic branching, olivaceous hue, black emorient patches, conspicuous pale brownish, fusiform pseudocyphellae, and numerous perpendicular, more or less basally constricted, side branches.

A recent field study indicated that thalli of the beard lichen Ramalina usnea undergo diffuse (“intercalary”) growth throughout their length. We examined thallus sections with TEM to better understand how the highly thickened cell walls of the prosoplectenchymatous cortex behave under conditions of continued expansion. Cell protoplasts were surrounded by massive accumulations of structured electron-dense wall layers interspersed with amorphous, electron-transparent substances, visible as concentric rings in transverse section. Nearest the protoplast, electron-dense wall layers were distinct and more or less alternated with irregular deposits of electron-transparent material. With increasing distance from the protoplast, the electron-dense wall layers were increasingly disrupted and intermixed among the electron-transparent materials. New cell branches grew through the accumulated wall materials, interrupting the layers they penetrated while producing their own concentric wall layers. The differing amounts of cell wall material accumulated was further indication of the different relative ages of such neighbouring cells. These observations suggest that cell walls are disrupted by diffuse tissue expansion and continually replaced by new walls and wall materials deposited to their interior at the interface with the protoplast. This pattern of development, documented previously in R. menziesii and U. longissima, suggests that component cells of lichen prosoplectenchyma behave quite differently from those of diffusely expanding filaments studied in non-lichen-forming fungi, where a single, discrete cell wall is maintained throughout growth.

Arctoparmelia collatolica is described as a species new to science based on morphological, chemical and molecular data. The species is similar to the usnic acid-deficient chemotype of A. centrifuga but differs in the grey-brown to brown upper surface in the central part of the thallus and ivory white to pale brown rhizines. The species contains collatolic acid and its derivatives. Seven secondary lichen substances are reported as new for the genus Arctoparmelia. A key to Arctoparmelia taxa is provided.

Peltigera globulata Miadl. & Magain, a new species in the P. ponojensis/monticola species complex of section Peltigera, is formally described. This clade was previously given the interim designation Peltigera sp. 17. It is found in sun-exposed and xeric habitats at high altitudes in Peru and Ecuador. Peltigera globulata can be easily recognized by its irregularly globulated margins covered mostly by thick, white pruina, somewhat resembling the sorediate thallus margins of P. soredians, another South American species from section Peltigera. The hypervariable region of ITS1 (ITS1-HR), which is in general highly variable among species of section Peltigera, does not have diagnostic value for species identification within the P. ponojensis/monticola complex. Nevertheless, no significant level of gene flow was detected among eight lineages representing a clade of putative species (including P. globulata) within this complex. ITS sequences from the holotype specimens of P. monticola Vitik. (collected in 1979) and P. soredians Vitik. (collected in 1981) and lectotype specimens of P. antarctica C. W. Dodge (collected in 1941) and P. aubertii C. W. Dodge (collected in 1952) were successfully obtained through Sanger and Illumina metagenomic sequencing. BLAST results of these sequences revealed that the type specimen of P. monticola falls within the P. monticola/ponojensis 7 clade, which represents P. monticola s. str., and confirmed that the type specimen of P. aubertii falls within a clade identified previously as P. aubertii based on morphology. The ITS sequence from the type specimen of P. soredians, which superficially resembles P. globulata, confirms its placement in the P. rufescens clade. Finally, we discovered that the name P. antarctica was erroneously applied to a lineage in the P. ponojensis/monticola clade. The ITS sequence from the type specimen of P. antarctica represents a lineage within the P. rufescens clade, which is sister to the P. ponojensis/monticola clade.

A new lichen species, Lecanora zeorina Li J. Li & Printzen is described here from the south-west of China. Lecanora zeorina is characterized by its somewhat areolate-squamulose thallus, zeorine to lecanorine apothecia, an epihymenium without crystals around expanded paraphyses tips, an amphithecium with large calcium oxalate crystals and the production of atranorin. A new combination, Lecanora crystalliniformis (B.G. Lee & Hur) Li J. Li & Printzen, is based on Protoparmeliopsis crystalliniformis B.G. Lee & Hur, which was described as a new species from South Korea. Collections from China are almost identical in morphology and chemistry, and are phylogenetically closely related. Phylogenetic reconstructions based on ITS and mtSSU suggest that these two lecanoroid species belong in Lecanora s. str. where they form a sister group to sorediate species such as L. barkmaniana Aptroot & Herk and L. variolascens Nyl. Detailed descriptions, discussions, distributions and phylogenetic trees, based on multiple collections, are presented.