Nordic equiseticolous Pyrenomycetes

The Pyrenomycete flora on Equisetum has been studied, mainly on Nordic material. With regard to frequency and host specificity these fungi can be divided into three groups, viz. 1) true Equisetum fungi; 2) common species but not restricted to Equisetum; 3) accidental species. An annotated list is given of the two first categories which comprise the following taxa. 1: Didymosphaeria equiseti–hiemalis, Phaeosphaeria berlesei, P. equiseti, Mycosphaerella equiseti, M. equiseticola, Scirrhia castagnei, S. silvalica, and probably Didymella equisetina. 2: Phaeosphaeria eustoma, P. fuckelii, Mycosphaerella cf. aspidii.Two new taxa and one new combination are published, viz. Phaeosphaeria equiseti (Karst.) L. & K. Holm comb, nov., P. equiseti var. lindii L. & K. Holm var. nov., Scirrhia silvalica L. & K. Holm sp. nov.