Stems to 1 cm. Leaves 0.7--0.9 mm, ligulate to short-lanceolate, bordered above by 1--5 rows of less papillose, thick-walled cells; apex broadly acute; costa ending 2--4 cells before the apex, abaxially papillose; distal laminal cells 10--12 µm wide, 1:1, walls thin in medial portion of leaf, lumens quadrate, proximal cells thin-walled throughout.

Soil, rarely on decorticating bark, rocky places at higher elevations in the Southern Appalachians and in the southwestern states; 1350--2200 m; Ariz., N.C., N.Mex., Tex.; Mexico; Central America; South America; Europe; Asia; Africa; Pacific Islands (Hawaii).

The gemmae elsewhere commonly found on stalks in leaf axils were not seen in the range of the flora. The dentate, bordered leaves are immediately diagnostic of this species, while the anatomical characters of the genus will confirm the identification. Although the range of this species is presently restricted to the Southern Appalachians in the range of the flora, 40,000-year-old subfossils have been found (J. A. Janssens and R. H. Zander 1980) at a site in the Yukon. Dichodontium pellucidum is commonly mistaken for this species, but is easily distinguished by the dentate distal abaxial surface of the costa. Barbula convoluta is also similar but has quadrate adaxial costal cells and a distinct stem central strand.