The fertile fronds of Asplenium platyneuron are longer and more erect than the sterile fronds, but are otherwise similar. If both sterile and fertile fronds are not present, or if the difference between fertile and sterile fronds is not recognized, this species may be recognized by other features. The blades are once pinnate with a basal auricle that often overlaps the rachis. Sori are clearly elongate and are not borne on the margins of the segments.

Asplenium platyneuron ranges from Kansas and Texas to Florida and Maine, but extends only into southwestern Wisconsin, north to Columbia and Lacrosse Counties, except for one report from Door County. The plants often grow on soil, as opposed to species that most often grow on rocks. Habitat is not specific, but it appears to favor disturbed forests.