[2] Woolly lipfern is a small evergreen fern,[3] growing in tufts or clusters and bearing hairs on most of its leaf surfaces.

They have a broad, dark, central stripe which is sharply differentiated from the narrow, light brown,[5] orange-tan,[4] or pale reddish-brown margins.

[7] The rachis (leaf axis) is rounded on the upper side, dark brown in color, and bears soft hairs of uniform shape, and scattered linear scales.

[5][3] On their underside, they bear multiple rows of linear scales, not more than 0.1 to 0.4 mm wide, loosely overlapping, but not concealing the leaf surface, with a truncate base and without cilia at their edges.

(This character distinguishes the species from the similar Myriopteris rufa, where the scales of the costa are broad and do conceal the leaf surface.)

[3] On fertile fronds, the sori are protected by false indusia formed by the edge of the leaf curling back over the underside.

Reproduction is apogamous: triploid spores are formed by mitosis, rather than meiosis, and grow into gametophytes, which sprout a genetically identical sporophyte without fertilization.

[5] Small specimens might be confused with M. gracilis, but that species has only hairs proper, rather than the narrow scales present in M. tomentosa.

[10] Early generic classifications, including that of Carl Borivoj Presl in 1836[12] placed the species in a broadly circumscribed Cheilanthes, a treatment followed by most authors until the 21st century.

In 1841, John Smith moved the species to Notholaena as N. tomentosa, recognizing the genus as separate from Cheilanthes based on venation and soral placement;[13] however, this name was illegitimate, having already been used by Desvaux in 1813.

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.

Members of the "core covillei" clade, including M. tomentosa, have leaves finely divided into bead-like segments.

Within this clade, M. tomentosa is part of a subclade including M. chipinquensis, M. jamaicensis, M. myriophylla, M. rufa, and M. windhamii, most of which are apogamous.

[24] Woolly lipfern typically grows on rocky slopes, in crevices, and on ledges, on a variety of rocks such as limestone or granite.