Asplenium trudellii Wherry. Phen: May-Oct. Hab: Moist outcrops of felsic sedimentary or metamorphic rocks, such as sandstone, phyllite, schist, at low elevations. Dist: N. NJ, sw. PA, s. OH, and s. IL south to w. NC, c. GA, n. AL; recently located west of the Mississippi River in Baxter County, n. AR (Peck 2011).
Origin/Endemic status: Endemic
Taxonomy Comments: This taxon is an (allegedly) sterile triploid hybrid (MMR) of A. montanum and A. pinnatifidum. However, there is direct evidence that it can produce fertile spores. Moreover, it is additionally considerably more common than most other (allegedly) sterile Asplenium hybrids, sometimes occurring without one or both parents, suggesting that it may be able to disperse independently. I therefore treat it as a species of hybrid origin, rather than a sterile hybrid, and omit the "hybrid ×" from its name.
Synonymy: = Sf; = ×Asplenosorus trudellii (Wherry) Mickel; = Asplenium ×trudellii Wherry (pro sp.) – C, F, FNA2, Il, K1, K3, Pa, WV; = Asplenium montanum × pinnatifidum; = Asplenium pinnatifidum Nutt. var. trudellii (Wherry) Clute – G; = n/a – RAB