Trudell's spleenwort is intermediate in form between its two parents, and is generally found near them, growing on exposed outcrops of acidic rock.

It is similar to A. pinnatifidum, with a triangular leaf blade, pinnatifid (lobed) in the upper part, with a long, drawn-out tip.

[3] The rhizome is presumably covered in clathrate scales (bearing a lattice-like pattern), as in the other Aspleniums, including its parent species.

[6][5] However, the species has been observed, particularly along the lower Susquehanna River, to form colonies, suggesting that it undergoes independent reproduction.

This specimen was collected in 1961 on a sandstone cliff at Cumberland Falls State Resort Park, and identified as A. pinnatifidum × trudellii.

He chose for a type specimen a sample he had collected with Harry W. Trudell in July 1920 from Cully ravine, just below the Holtwood Dam.

[12] Other herbarium specimens from York Furnace, Pennsylvania, Harpers Ferry, West Virginia, and Winston County, Alabama were retrospectively identified with the new taxon,[1] as were specimens collected by Edward W. Graves at Long Island, Alabama in 1917.

[3] Wherry initially speculated that it was either a hybrid between A. montanum and A. pinnatifidum, or a common descendant with them from a hypothesized acid-soil ancestor.

)[13] In 1974, John Mickel published Asplenosorus trudellii as a new combination for the species to allow the continued recognition of the genus Camptosorus for the walking ferns.

[14] Since then, phylogenetic studies have shown that Camptosorus nests within Asplenium,[15][16] and current treatments do not recognize it as a separate genus.

[17] It is known from Blairstown, New Jersey[18] (where it is now extinct) southwest in the Appalachian Mountains through Pennsylvania, Maryland, Virginia, West Virginia, Ohio, North Carolina, Kentucky, Tennessee, Georgia and Alabama, and in the Shawnee Hills in Jackson County, Illinois.

[17] The type specimen was found growing in mediacid (pH 3.5–4.0) soil, on "quartzose mica-schist ledges".