Wallace R. Weber and Robert H. Mohlenbrock. This form lacked dark color in the stipe and rachis except for the very base; some slightly larger specimens, with a frond, retained the normal coloration of these structures. Among fertile species, A. bradleyi most closely resembles its parent species A. montanum. Several characteristics exit to distinguish them: the pinnae of A. bradleyi are toothed and less deeply lobed or cut than A. montanum (where the pinnae are often fully cut to pinnules), the dark color of the stipe extends into the rachis, the upper pinnae lack stems, and the overall shape of the leaf blade is parallel-sided, rather than lance-shaped. A. bradleyi also shows some resemblance to black spleenwort (A. adiantum-nigrum) (although their ranges do not overlap). The latter may be identified by its distinctly triangular-shaped leaf blade, more deeply cut leaves (the pinnules of its basal pinnae are lobed), and enlarged basiscopic, rather than acroscopic, pinnules. Asplenium bradleyi is similar to two hybrid species of which it is a parent, Graves' spleenwort (A. × gravesii), a hybrid with A. pinnatifidum, and Wherry's spleenwort (A. × wherryi), a backcross with A. montanum. In A. × gravesii, the dark color of the stipe ends at the base of the leaf blade, the pinnae are more shallowly lobed and the enlargement of acroscopic lobes or pinnules is less distinct, and the apical portion of the blade forms a long, tapering tip with slight lobes (as in A. pinnatifidum), rather than being cut into pinnae. In addition to the general reduction of the toothiness of A. bradleyi, A. × gravesii also shows faint winging along the stipe. Likewise, in A. × wherryi, the dark color of the stipe again ends at the base of the leaf blade, the overall shape of the blade tends to be more distinctly lance-shaped, and the fronds are somewhat more deeply cut than A. bradleyi, progressing from bipinnate in the lower half to pinnate-pinnatifid and finally pinnate at the apex. Finally, the diploid hybrid A. montanum × platyneuron, from which A. bradleyi arose by chromosome doubling, is essentially identical in appearance to A. bradleyi. On close examination, its spores are found to be abortive, and the sori are smaller and not do not become fused with each other as they grow, as they do in fertile A. bradleyi. Taxonomy The scientific discovery of A. bradleyi occurred in 1871, when Frank