Athyrium filix-femina subsp. angustum (Willdenow) R.T. Clausen
Athyrium filix-femina subsp. angustum (Willdenow) R.T. Clausen is a synonym sensu FNA Ed. Comm., 1993 of:
Athyrium filix-femina var. angustum (Willdenow) G. Lawson, an accepted variety name sensu FNA Ed. Comm., 1993.