More technical description adapted from Burke Herbarium:[4] Myriopteris gracillima is a lithophytic perennial, with leaves emerging from short creeping stems that are 4–8 mm (0.2–0.3 in) in diameter with narrow scales that are uniformly brown or with a weakly defined dark central stripe; the scales are straight to somewhat contorted, loosely appressed, and persistent.

It is also found at low elevation in the Columbia River gorge only in the region where it transects the Cascade Mountain range,[4][2] presumably because of higher precipitation.

During an extended dry period leaves curl and expose their hairy abaxial (lower) surface, presumably to reduce water loss.

[5] The specific epithet gracillima, meaning "very slender",[6] presumably refers to the linear scales on the leaf axes, which Eaton described with that word.

Convergent evolution in arid environments is thought to be responsible for widespread homoplasy in the morphological characters traditionally used to classify it and the segregate genera that have sometimes been recognized.

On the basis of molecular evidence, Amanda Grusz and Michael D. Windham revived the genus Myriopteris in 2013 for a group of species formerly placed in Cheilanthes.

[8] In 2018, Maarten J. M. Christenhusz transferred the species to Hemionitis as H. gracillima, as part of a program to consolidate the cheilanthoid ferns into that genus.