Athyrium angustum, the northern lady fern, is a fern native to northeastern North America.

[3][4] It was long included in the superspecies Athyrium filix-femina, but is now largely recognized as a distinct species.

Athyrium angustum has a more southern counterpart — Athyrium asplenioides, the southern lady fern — that is very similar.

[5] The latter has a broader frond, especially at the base.

This Polypodiales-related article is a stub.