66 Dryopteris cristata (L.) A. Gray

This species s. str. occurs in Eurasia and N. America. Thus, it belongs to the amphi-atlantic plants (Hultén, Amphi-atl., p. 58 and map 40). In eastern N. America closely related taxa occur, viz. D. clintoniana (D. C. Eat.) Dow. (previously taken as a variety of D. cristata), mapped here, and D. celsa (W. Palm.) Small. Cf. also Meusel et al. 1965, map p. 17.