Athyrium filix-femina var. cyclosorum

Petiole 15–45 (–60) cm, base densely scaly; scales brown or dark-brown, lanceolate or ovatelanceolate, (7–) 10–20 × (1–) 2–5 mm, ± crisped. Blade elliptic to oblanceolate, 1–2-pinnate-pinnatifid, 25–120 × 10–50 cm, gradually narrowed proximally, broadest at or just above middle, apex acuminate. Pinnae very short-stalked or sessile, linear-oblong or oblong, apex acuminate. Pinnules sessile, narrowly deltate or oblong-lanceolate, base basiscopically broadly cuneate, acroscopically truncate, ± auriculate, apex obtuse to ± acute. Rachis, costae, and costules glabrous or with scales or pale glands. Sori round to elliptic, hooked at distal end, or horseshoe-shaped, medial to supramedial; indusia long-ciliate with nonglandular marginal hairs as long as or longer than width of indusia. Spores yellow. 2n = 80.

Habitat: Moist woods, swamps, streambanks
Elevation: 10–1600 m

Alta., B.C., Man., N.W.T., Ont., Que., Sask., Yukon, Alaska, Calif., Idaho, Mont., Oreg., S.Dak., Wash., Wyo.

Discussion

Athyrium filix-femina var. cyclosorum is most similar to the European var. filix-femina; it differs in having broader, nearly equilateral pinnules and medial to supramedial sori. The variety is distributed in northwestern North America with disjunct populations in northwestern Quebec and Ontario.

Selected References

None.

Lower Taxa