It was more commonly called Asplenium ebeneum, a name published by William Aiton in 1789, until the rediscovery and revival of the Linnaean epithet in the late nineteenth century.

A. platyneuron f. hortonae, a sterile form with the pinnae cut to toothed pinnules, and f. furcatum, with forking fronds, are still recognized.

Long-distance dispersal may also explain its naturalized appearance in South Africa, and the existence of an isolated population found in Slovakia in 2009, its first known occurrence in Europe.

Ebony spleenwort is a small fern with pinnate fronds, growing in tufts, with a shiny reddish-brown stipe and rachis.

[7][8] An indusium covers each sorus; these are whitish and translucent[3] or silvery[2] with a slightly toothed or erose (irregularly jagged) edge,[3] soon withering to reveal the sori.

[13] Maidenhair spleenwort, A. trichomanes, is also pinnately cut with a dark, glossy rachis, but the pinnae are oval and somewhat rounded rather than broadly oblong, usually less than two times as long as wide.

[19] The first description listed was that of Jan Gronovius, botanist and mentor of Linnaeus, in his Flora Virginica of 1743, based on a specimen collected by the collector John Clayton.

[20] In 1789, the species was independently described by William Aiton in Hortus Kewensis, and given the name Asplenium ebeneum,[21] referring to the ebony color of its stalk.

[27] The transfer of Linnaeus' specific epithet to form the name Asplenium platyneuron was mooted by D. C. Eaton in 1878, who attributed the combination to a pencil notation by William Oakes in the margin of a copy of Flora Virginica.

However, in 1981, David B. Lellinger pointed out that Eaton had not, in fact, accepted the combination in 1878, preferring the more descriptive epithet ebeneum to the less accurate through senior platyneuron.

[27] Eaton aside, the first valid publication of Asplenium platyneuron was that of Britton, Emerson E. Sterns, and Justus F. Poggenburg in 1888, which implicitly references Linnaeus's basionym.

[30] The species has twice been placed in genera segregated from Asplenium: as Chamaefilix platyneuros by Oliver A. Farwell in 1931,[31] and as Tarachia platyneura by Sizuo Momose in 1960.

[5] A global phylogeny of Asplenium published in 2020 divided the genus into eleven clades,[33] which were given informal names pending further taxonomic study.

[42] According to Taylor et al., this variety may be recognized by a longest pinna length greater than 3.5 centimeters (1.4 in) and the almost universal presence of sori on erect fronds.

[37] They described it as bearing fertile fronds up to 70 centimeters (28 in), with as many as seventy pinnae, and a coarse appearance with roughly toothed leaf edges intergrading with A. platyneuron var. incisum.

[43] Herb Wagner and David M. Johnson, who collected similar material in Cass County, Michigan (well to the northwest of the supposed range of the variety) did not consider morphological variation in var.

[46] As these plants occur throughout the range of the species intermixed with typical specimens and intergrading with them morphologically, Wagner and Johnson did not think them worth of taxonomic recognition.

[38] Another taxon characterized by deeply incised margins was described in 1901 by George E. Davenport as Asplenium ebeneum var. hortonae.

[60] While Wagner and Johnson declined to distinguish most infraspecific taxa within A. platyneuron, they did recognize f. hortonae as a "rare sterile form".

[38] A form with forked fronds was known around the end of the nineteenth century, and was formally described in 1909 by Willard Clute as A. platyneuron f. furcatum.

[61] Robert M. Tetrick II discovered similar plants in West Virginia, which he described as having "fronds much branched, the ultimate divisions crested" and named A. platyneuron f. multifidum.

[67][68][69] In 1924, Frederick G. Floyd argued that the formation of these proliferations was a normal characteristic of the species, which appeared regularly, if not universally, and did not warrant a varietal designation.

[70] Floyd's position was not universally accepted: Louise Tanger made a new combination for the form, A. platyneuron f. proliferum in 1933,[71] and Taylor et al. recognized it in a discussion of infraspecific taxa in the species in 1976.

[73][74] A backcross between A. bradleyi and A. platyneuron is believed to have been collected twice, from a now-destroyed site in Pennsylvania,[75] and in a preliminary report from Sequatchie County, Tennessee.

[90] In South Africa, it is generally found at altitudes over 600 meters (2,000 ft), in habitats similar to those it prefers in North America (under small bushes and on rocky banks).

[97] A variety of adaptations make A. platyneuron an aggressive colonizer, even weedy, when compared with other spleenworts, although a warming climate and an increase in second growth habitats may also have played a role in its expansion in the Great Lakes region.

[89] The starchy stipe bases provide energy for rapid growth in the spring, allowing the fronds to keep ahead of competing vegetation.

This has allowed ebony spleenwort to be an early colonizer, from distant locations, of recently disturbed habitats, such as coal spoils in southern Iowa.

[98] The appearance of A. platyneuron in a disturbed habitat in Slovakia, 6,500 kilometers (4,000 mi) from the nearest known sites in eastern North America, is probably the result of long-distance dispersal, which may also have allowed it to colonize and naturalize in South Africa.

[99] While globally secure (G5), ebony spleenwort is considered an endangered species in some of the states and provinces at the northern and western edges of its North American range.