Asplenium pinnatifidum Nuttall. Phen: May-Oct. Hab: Fairly moist to very dry outcrops of felsic sedimentary or (mostly low-grade) metamorphic rocks, such as sandstone, phyllite, and schist, at low to moderate elevations. Dist: NY (historically), NJ, se. PA, wc. PA, s. OH, IN, IL, and MO south to w. NC, c. GA (Jones & Coile 1988), AL, n. MS, AR, and e. OK.
Origin/Endemic status: Native
Taxonomy Comments: This species is a fertile allotetraploid derived from hybridization of A. montanum and A. rhizophyllum; its chromosome complement is symbolized MMRR.
Synonymy: = Ar, C, F, FNA2, Il, K3, Mo1, NY, Ok, Pa, RAB, S13, Sf, Tat, Tn, Va, W, WV; = ×Asplenosorus pinnatifidus (Nutt.) Mickel; = Asplenium ×pinnatifidum – K1; = Asplenium pinnatifidum Nutt. var. pinnatifidum – G