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 viride Asplenium viride Asplenium viride is known as the green spleenwort because of its green stipes and rachides. This feature easily distinguishes this species from the very similar-looking maidenhair spleenwort, "Asplenium trichomanes". Green spleenwort was described by Carl Linnaeus in his 1753 "Species Plantarum", under the name ""Asplenium Trich. ramosum"", with a type locality of "'" (rocks in Caernarfonshire). Under the rules of the International Code of Botanical Nomenclature, phrase names such as ""Asplenium Trichomanes ramosum"" are to be treated as orthographic errors – in this case, for ""Asplenium ramosum"". That name was later rejected in favour of William Hudson's later