Dryopteris filix-mas (Linnaeus) Schott ssp. brittonii Fraser-Jenkins & Widén. Phen: Late Jun-early Sep. Hab: Limestone talus. Dist: NL west to ON, south to w. PA, c. OH, n. MI, and n. WI.
Origin/Endemic status: Native
Taxonomy Comments: The D. filix-mas complex is very unclear and needs critical work. European material, which differs significantly from North American material, has been considered to be the allopolyploid hybrid of D. caucasica × oreades, unlikely to be the parents of North American "filix-mas".
Synonymy: = K3, K4, NE; = n/a – Pa; < Dryopteris filix-mas (L.) Schott – C, F, FNA2, G, GrPl, Montgomery & Paulton (1981)