Alpine Ladyfern, American Alpine Lady Fern:: Athyrium distentifolium ssp. americanum (Synonyms: Athyrium alpestre var. americanum, Athyrium americanum, Athyrium distentifolium var. americanum) - Plants of subalpine slopes. Indusium absent.
Common Ladyfern, Lady Fern, Northwestern Lady Fern, Subarctic Lady Fern: Athyrium filix-femina ssp. cyclosorum (Synonyms: Athyrium alpestre var. cyclosorum, Athyrium filix-femina var. cyclosorum) - Plants of moist, low- to mid-elevation forests. Indusium present.