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
What Is Life in the UK as perhaps the strongest of all of Harrison's singles. Writing in 1981, "NME" critic Bob Woffinden grouped "What Is LIfe" with "My Sweet Lord", "Isn't It a Pity" and "Awaiting on You All" as "all excellent songs". Reviewing the 2001 reissue of "All Things Must Pass", for "Rolling Stone", James Hunter wrote of how the album's music "exults in breezy rhythms", among which "the colorful revolutions of 'What Is Life' ... [move] like a Ferris wheel". The following year, in Rolling Stone Press's "Harrison" tribute book, David Fricke included "What Is Life" among his selection of "essential