The lichenicolous fungi Arthrorhaphis aeruginosa R. Sant. & Tønsb. On Cladonia spp. and Arthrorhaphis olivaceae R. Sant. & Tonsb. on Melanelia olivacea are described as new from Norway, Scotland and western North America, and from Sweden, respectively.

Abrothallus secedens Wedin & R. Sant. sp. nov., commensalistic on species of Pseudocyphellaria, from Argentina and Kenya and Abrothallus granulatae Wedin sp. nov., parasitic on Pseudocyphellariagranulata, from Argentina (Tierra del Fuego) are described. Vouauxiomycesgranulatae Wedin sp. nov., is regarded as the anamorph of A. granulatae. Sphaerellothecium minutum Hafellner is recorded for the first time from Antarctica and South America, Phaeosporobolus alpinus R. Sant., Alstrup & D. Hawksw. from Antarctica and Argentina, Arthonia epiphyscia Nyl., Dacampia rufescentis (Vouaux) D. Hawksw., Polycoccum pulvinatum (Eitner) R. Sant. And Stigmidium pumilum (Lettau) Matzer & Hafellner from South America and Nesolechia oxyspora (Tul.) Massal. and Pyrenidium actinellum Nyl. from Chile.

All species of Antarctic Acarosporaceae (s. lat., including Biatorellaceae) with yellow thalli are revised. Four genera, Acarospora, Biatorella, Biatorellopsis, Eklundia, and ten species, all of them endemic, were previously reported from Antarctica. Our results indicate that in Antarctica Acarospora subgen. Xanthothallia s. str. includes only two species, A. gwynnii Dodge and A. flavocordia sp. nov.; Biatorella does not occur in Antarctica, the species described by Dodge belonging instead in Candelariella; the genus Eklundia is a synonym of Candelariella; Biatorellopsis does not occur in Continental Antarctica, and the genus is a synonym of Pleopsidium; Pleopsidium is represented in Antarctica by one species, P. chlorophanum, which was treated under very different generic and specific names by earlier authors. Altogether, the number of species of yellow Acarosporaceae known from Antarctica is reduced from ten to three, distributed in two genera: Acarospora and Pleopsidium. The two Acarospora species, A. gwynnii and A. flavocordiaare apparently endemic to Antarctica, whereas P. chlorophanum is a widespread bipolar lichen. A comprehensive list of synonyms and a key are provided.

Twelve species of Sticta are recorded from southern South America,(Argentina and Chile including Juan Fernandez) south of latitude 30°S, viz., S ainoae, S. caulescens, S. fuliginosa, S. gaudichaldia, S. hypochra, S. hypopsila, S lineariloba, S. limbata, S. longipes, S. sublimbata and S. weigelii, and S. santessonii D Galloway is newly described. A key is provided, and details of anatomy, morphology, distribution, ecology and taxonomy are discussed.