Plants in thin to dense mats, light- to yellow-green, glossy. Stems to 4 cm, 1--3 mm wide, complanate, radiculose ventrally. Leaves flaccid, appressed-imbricate, somewhat concave or flat, smooth, symmetric to somewhat asymmetric, 0.9--2 × 0.4--0.8 mm, ovate to ovate-lanceolate, rarely oblong-lanceolate or oblong-ovate, acuminate or often abruptly narrowed to an acute or filiform apex, margins plane or narrowly recurved for a short distance at base, serrulate to strongly serrate beyond leaf middle, serrate to serrulate proximally; costa very short and double or lacking; cells smooth; median cells 47--136 × 7--12 µm; alar cells 12--27 × 9--17 µm, quadrate to short-rectangular, in 1--several rows with 3--8 cells in the marginal row. Sexual condition dioicous. Perigonia unknown. Perichaetia small, numerous, the bracts lanceolatae to ovate-lanceolate, acuminate. Seta yellowish brown to red, flexuose, 0.7--1 cm. Capsule yellowish brown to light brown, cernuous, 0.8--1.5 × 0.3--0.5 mm, oblong or ovoid, straight or arcuate, when dry contracted below mouth and tapered to a wrinkled neck; opercula obliquely rostrate, 0.3--0.5 mm. Spores 11--13 µm.

Capsules extremely rare but evidently mature in fall. Shaded siliceous or calcareous soil and rock, often on bases of trees, exposed tree roots, and rotten logs, sometimes in cedar swamps; 60--2700 m; Man., N.B., Ont., Que., Sask.; Ariz., Ark., Conn., D.C., Ga., Ill., Ind., Iowa, Kans., Ky., Md., Mass.(Mishler & Miller 1983), Mich., Minn., Mo., Nebr., N.H., N.J., N.Mex., N.Y., N.C., Ohio, Pa., S.Dak., Tenn., Vt., W.Va., Va., Wis.; Mexico; Central America (Honduras).

This species is widespread in northeastern North America with disjunct populations in Saskatchewan, Quebec, New Brunswick, Arizona and New Mexico. Taxiphyllum deplanatum has often been confused with T. taxirameum but the two are easily distinguished superficially and microscopically. The flaccid, appressed-imbricate leaves characteristic of T. deplanatum will easily separate the species from T. taxirameum with its rigid, usually distant, wide-spreading to squarrose leaves. The alar regions of T. deplanatum are well differentiated with quadrate to short-rectangular cells, 3--8 in the marginal rows, which is in striking contrast to the poorly differentiated alar regions of T. taxirameum that have only a few rectangular cells on the margins. Taxiphyllum deplanatum has been reported for the Gulf Coast region, based on a Louisiana specimen (R. R. Ireland 1969), however, it was later re-examined and found to be a misidentified specimen of T. taxirameum as W. R. Reese (1984) noted.