Dryopteris carthusiana (Villars) H.P. Fuchs. Phen: Jun-Oct. Hab: Acidic, organic-rich bogs, swamps, less frequently in moist rocky ravines, rich forests, and sloping rock outcrops. Dist: Irregularly circumboreal, in North America ranging from n. QC west to YT, south to NC, SC, ne. GA, TN, AR, NE, w. MT, and WA.
Origin/Endemic status: Native
Taxonomy Comments: This species is a fertile allotetraploid derived from hybridization of Dryopteris intermedia and "Dryopteris semicristata", a hypothetical species which may now be extinct. Its chromosome complement is symbolized IISS. The triploid backcross Dryopteris ×triploidea (Dryopteris carthusiana × intermedia, with chromosome symbolized IIS) is frequent in areas with both parents present.
Synonymy: = Ar, C, FNA2, Il, K1, K3, K4, Mo1, NE, NY, Pa, Tn, Va, W, Montgomery & Paulton (1981); = Dryopteris austriaca (Jacq.) Woyn. ex Schinz & Thell. var. spinulosa (O.F.Müll.) Fiori – G; = Dryopteris spinulosa (O.F.Müll.) Watt – GrPl, RAB, S13, Sf, Tat, WV; = Dryopteris spinulosa (O.F.Müll.) Watt var. spinulosa – F