The present contribution to lichen−forming and lichenicolous biota of northern− most Billefjörden (Petuniabukta area, central Spitsbergen, Svalbard) contains 40 species of lichens. Four species: Arthonia ligniariella, Candelariella lutella, Ochrolechia upsaliensis, Polyblastia pernigrata are new for the Svalbard Archipelago.
Formerly reported as maritime Antarctic Bacidia sp. A has been re-named here as B. chrysocolla Olech, Czarnota et Llop. Another new species, B. subcoprodes Olech et Czarnota, found in the continental and maritime Antarctic has also been described here. A placement of both taxa within Bacidia De Not. is probably tentative because they are not congeneric with the type of this genus, B. rosella (Pers.) De Not. Similarities to other Bacidia with Laurocerasi-brown hypothecium and mostly 3-septate ascospores are discussed.
Information on lichens of Franz Josef Land is summarized based on original and literature data. Two hundred twenty nine lichen species are documented, of which 59 species and two varieties are newly reported for this territory. This represents only 13% of the Arctic lichen flora richness. We have found 28 rare lichen species in the archipelago and recommend to include 9 species in the Red Data Book of the Arkhangelsk Region of Russia.