59 Matteuccia struthiopteris (L.) Tod.

This moderately variable, boreal-montane species occurs in Eurasia and N. America. The American population forms a separate taxon which appears under several names, int. al. Pteretis pensylvanica (Willd.) Fem. Here it is included in the species in question, which in this sense belongs to the circumpolar plants (Hultén, Circumpol. I, p. 124 and map 115).