Stems short-creeping or ascending. Petiole straw-colored distally, 7–60 cm, base dark red-brown or black, swollen, with 2 rows of teeth; scales light to dark brown, linear- to ovate-lanceolate, 7–20 × 1–5 mm. Blade elliptic, lanceolate to oblanceolate, 2-pinnate to 2-pinnate-pinnatifid, 18–30 × 5–50 cm, herbaceous but with cartilaginous margin, narrowed to base, apex acuminate. Pinnae sessile to short-stalked, linear-oblong to lanceolate, apex acuminate. Pinnules pinnatifid, segments oblong-linear to narrowly deltate, margins serrate. Rachis, costae, and costules glabrous or with glands or hairs. Veins pinnate. Sori straight, hooked at distal end, or horseshoe-shaped; indusia dentate or ciliate.

Distribution

• Generated Map
• Legacy Map

Alta., B.C., Man., N.B., N.S., N.W.T., Nfld. and Labr. (Nfld.), Ont., P.E.I., Que., Sask., Yukon, Ala., Alaska, Ariz., Ark., Calif., Colo., Conn., Del., Fla., Ga., Idaho, Ill., Ind., Iowa, Kans., Ky., La., Maine, Mass., Md., Mich., Minn., Miss., Mo., Mont., N.C., N.Dak., N.H., N.J., N.Mex., N.Y., Nebr., Nev., Ohio, Okla., Oreg., Pa., R.I., S.C., S.Dak., Tenn., Tex., Utah, Va., Vt., W.Va., Wash., Wis., Wyo., Mexico, Central America, South America, Europe, Asia.

Discussion

Athyrium filix-femina is circumboreal, and this or closely related species extend into Mexico, Central America, and South America. The delimitation and infraspecific classification of A. filix-femina need detailed study.

Varieties ca. 5 (4 in the flora).

Selected References

None.

Lower Taxa

Athyrium filix-femina var. angustum, Athyrium filix-femina var. asplenioides, Athyrium filix-femina var. californicum, Athyrium filix-femina var. cyclosorum

Key

1	Petiole scales more than 1 cm; blades ca. 2 times length of petioles, elliptic to oblanceolate.	> 2
1	Petiole scales 1 cm or less; blades 1-1.5 times length of petioles, elliptic to lanceolate.	> 3
2	Pinnules narrowly deltate or oblong-lanceolate, nearly equilateral at base; indusia long-ciliate; spores yellow.	Athyrium filix-femina var. cyclosorum
2	Pinnules linear-oblong or linear-lanceolate, inequilateral at base; indusia dentate or long-ciliate; spores brown.	Athyrium filix-femina var. californicum
3	Petiole scales brown to dark brown; blades elliptic, narrowed to base, broadest near or just below middle; pinnae sessile or short-stalked; pinnules linear to oblong; indusia not glandular; spores yellow.	Athyrium filix-femina var. angustum
3	Petiole scales light brown to brown; blades ovate-lanceolate to lanceolate, slightly narrowed to base, broadest just above base; pinnae usually stalked; pinnules oblong-lanceolate to narrowly deltate; indusia glandular or not; spores dark brown.	Athyrium filix-femina var. asplenioides