Athyrium americanum (American alpine lady fern)

Athyrium (lady-fern) is a genus of about 180 species of terrestrial ferns, with a cosmopolitan distribution. It is placed in the family Athyriaceae, in the order Polypodiales. Its genus name is from Greek a- (‘without’) and Latinized Greek thureos (‘shield’), describing its inconspicuous indusium (sorus’ covering). The common name “lady fern” refers in particular to the common lady fern.

— Wikipedia