As part of a revision of the genus Acanthothecis s. lat. (Graphidaceae) in Brazil, an updated world key to the known species of the genus is presented. From Brazil, the following ten new species are described: A. latispora, with single-spored asci, large, muriform ascospores, and norstictic and stictic acids; A. megalospora, with single-spored asci, very large, transversely septate ascospores, and norstictic and protocetraric acids; A. multiseptata, with 8-spored asci, medium-sized and narrow, transversely multiseptate ascospores, and lacking secondary substances except terpenoids; A. norstictica, with 1–2-spored asci, large, muriform ascospores, and norstictic acid; A. oryzoides, with 8-spored asci, medium-sized, transversely septate ascospores, and norstictic acid; A. rimosa, with 2-spored asci, small to medium-sized, muriform ascospores, and stictic acid; A. roseola, with 1–2-spored asci, large, muriform ascospores, and norstictic, stictic and subnorstictic acids; A. saxicola, with 8-spored asci, small, 3-septate ascospores, and norstictic acid; A. subfarinosa, with 8-spored asci, small, 6–8-septate ascospores, and norstictic acid; and A. submuriformis, with 8-spored asci, small, submuriform ascospores, and lichexanthone. In addition, three further species are formally validated, namely A. bicellulata, A. farinosa and A. subabaphoides, and the new combination A. bicellularis is proposed, based on Acanthotrema bicellularis.

Five Graphis species are reported as new to Europe from the Mata Nacional do Buçaco, a region in Portugal where graphidoid Graphidaceae are abundant and diverse. The following species were identified: Graphis dendrogramma, G. duplicata, G. gonimica, G. librata and G. pyrrhocheiloides. An updated key is given to the Graphis species known from Europe. All those newly reported were identified with names corresponding to tropical species.

This study describes a new species of Hypotrachyna subgenus Parmelinopsis from the south-eastern Cerrado (Brazilian savannah), a biodiversity hotspot. The species is especially common in open vegetation, including urban environments. Hypotrachyna neohorrescens sp. nov. is morphologically and chemically similar to H. horrescens. Nevertheless, phylogenetic analyses of the nuITS and mtSSU regions revealed that H. neohorrescens is a distinct species and closely related to the North American H. mcmulliniana, differing by the size of the laciniae and ascospores.

Two species of lichenicolous fungi are described as new to science: Lichenotubeufia etayoi Zhurb. (on Trachyderma), with light orange perithecia up to 360 μm diam., non-fasciculate excipular hairs, and 10–13-septate ascospores, 110–162 × 3–5 μm; and L. tibellii Zhurb. (on Coccocarpia), with light orange perithecia up to 275 μm diam., non-fasciculate excipular hairs, and 5–12-septate ascospores, 50–100 × 3–4.5 μm. An updated key to the species of Lichenotubeufia is provided.

Lichen extinction occurs at rapid rates as a result of human activity, although species could potentially be rescued by conservation management based on ecophysiological knowledge. The boreal old forest cyanolichen Erioderma pedicellatum currently occurs in few sites worldwide. To protect it from extinction, it is essential to learn more about it. The last remaining good European site is a canyon with a waterfall, in a low-rainfall region of Norway. Here, a spatially restricted population of 1500–2000 thalli dominates the epiphytic vegetation of a small number of Picea abies canopies. We were able to document that 1) E. pedicellatum grew on thin branches with higher bark pH than is normal for P. abies in a canyon that provided an unusual combination of very high light, high air humidity, and cool temperatures in the growing season. However, the species did not inhabit the main waterfall spray zone. 2) Erioderma pedicellatum had a high light saturation point, high CO2 uptake at high light (≥ 600 μmol m−2 s−1) and cool temperatures (5–20 °C), and experienced strong suprasaturation depression of photosynthesis when fully hydrated. 3) It showed good tolerance of desiccation and high light; it was slightly more tolerant than the morphologically similar, but more common cyanolichen Pectenia plumbea. 4) The European population in its sunny habitat had higher water holding capacity than previously recorded in slightly shaded rainforest populations in Newfoundland, consistent with acclimation to compensate for high evaporative demands. Understanding the ecological niche and responses to critical environmental factors is essential for action plans to avoid extinction of E. pedicellatum. Methods used in this study could also be applicable for ecological understanding of other threatened lichen species.