Cystopteris tenuis (Michaux) Desvaux. Phen: May-Aug. Hab: Moist outcrops and cliffs of metamorphic and sedimentary rocks, occasionally in moist soils near rock outcrops or moist soil banks. Dist: NL (Newfoundland) west to MN and NE, south to VA, IL, MO, and AR (Peck 2011), and in the mountains to NC, TN, and n. GA.
Origin/Endemic status: Native
Syn: = Ar, FNA2, Il, K1, K3, K4, Mo1, NE, NY, Pa, Tn, Va, W, Shmakov, Batkin, & Vaganov (2018); = Cystopteris fragilis var. mackayi – C, F, G; < Cystopteris fragilis – WV