Asplenium rhizophyllum one collection on sandstone in the Shawnee Hills of Illinois. A triploid hybrid between walking fern and Tutwiler's spleenwort was accidentally produced in culture. A similar plant collected from limestone in Shepherdstown, West Virginia could have originated from the same parents, from an unreduced (diploid) gametophyte of Scott's spleenwort crossed with walking fern, or from an unreduced walking fern gametophyte crossed with ebony spleenwort. In 1813, Henry Muhlenberg listed lobed spleenwort as "Asplenium rhizophyllum" var. "pinnatifidum", although he did not provide a description distinguishing the variety from the typical species. It was described as the species "A. pinnatifidum" by Thomas
Asplenium × wherryi ("A. platyneuron") and mountain spleenwort. In theory, "A. × wherryi" might be found anywhere the ranges of its parental species overlap, stretching down the Appalachian Mountains from New York to Georgia and in the Shawnee Hills of Indiana and Kentucky. In practice, it is quite uncommon and scattered. It has been reported from New Jersey, Lancaster County, Pennsylvania, Virginia, Kentucky, and Whitfield County, Georgia. The Pennsylvania report consisted of a single plant which grew for a few years at Tucquan Glen. The type locality in New Jersey was reported destroyed in 1956, although "A. bradleyi" was rediscovered there in 1960.