A new natural hybrid in the appalachian asplenium complex and its taxonomic significance

Abstract

A new spleenwort hybrid, Asplenium pinnatifidum×trichomanes, from southern Illinois is nicely intermediate in morphology between the parents, and shows no pairing of its genomes: two sets of chromosomes from A.×pinnatifidum and one from A. trichomanes. Taxonomically the cross is significant for its bearing on the interpretation of the taxon A. stotleri Wherry, previously believed to have originated from the same parents. New studies of A. stotleri based upon materials from the now extinct type colony in West Virginia, and from a newly discovered extant colony in Arkansas, show clearly that this taxon is not the same as A. pinnatifidum×trichomanes. Comparisons with A.×bradleyi D. C. Eaton (the tetraploid of A. montanum×platyneuron) indicate that the taxon A. stotleri is similar in all respects except for its more rounded segments. Asplenium stotleri is therefore reinterpreted as a synonym of A.×bradleyi, of which it is regarded as a slightly differentiated local form.