A total of 29 pyrenomycetous species on Salix in Troms, N Norway are treated. Two new species are described: Herpotrichiella collapsa G. Mathiassen and Lophiotrema boreale G. Mathiassen. A new combination is proposed: Platystomwn curtwn (Fr.) G. Mathiassen. New to Scandinavia is Glyphiwn schizosporwn. Nine species are new to Norway: Anthostomella melanotes, Keissleriella cladophila, Lophiostoma quadrinucleatwn, Lophiotrema nucula, Melanomma fuscidulwn, Platystomwn curtwn, Rebentischia massalongii, Rhynchostoma minutwn and Saccardoella transsylvanica. Eleven species are new to Troms: Amphisphaerella xylostei, Berlesiella nigerrima, Chaetosphaeria pomiformis, Cryptodiaporthe salicella, Diatrype bullata, Enchnoa infernalis, Hysterographiwn elongatwn, Kirschsteiniothelia aethiops, Leptosphaeria hendersoniae, Lophiostoma macrostomoides and Platystomwn compresswn. The remaining six species have previously been reported from Troms: Arthropyrenia lapponina, Bertia moriformis var. moriformis, Cryptosphaeria subcutanea, Hypoxylon macrosporwn, H. mammatwn and Melanomma pulvis-pyrius.
A dichotomous key is followed by descriptions of the species in alphabetic order. The ecology and systematics of the different species are discussed, and some difficult genera are commented upon. Comments are given on the ecology and distribution of the different Salix species in Troms.
