Plants 1-1.5 mm. Leaves lingulate to oblong-ovate, 0.6-1.3 mm, margins revolute from near apex to near base, smooth-celled in the middle and base, apex round to slightly emarginate; costa excurrent, with an abaxial epidermis, filaments of 2-6 cells, cells subspheric, with several papillae per cell, terminal cell subspheric; cells of leaf base 24-66 µm, medial and distal cells 13-26 µm, with several papillae on either side of distal and median cells. Sexual condition cladautoicous. Seta 9-13 mm. Capsule urn oblong-cylindric, 1.5-2.3 mm; operculum 0.7-1.1 mm; peristome strongly twisted, 1015-1100 µm. Spores spheric, finely papillose, 11-13 µm.

Capsules mature Jan-Jul. Sandy soil or rocks, along dry washes, in open or shaded places in deserts; moderate elevations (400-600 m); B.C.; Ariz., Calif., Nev., N.Mex.; Mexico (Baja California); Europe (France, Spain, Switzerland).

The leaf cells with several papillae on either free surface distinguish Crossidium seriatum from C. aberrans. A poorly preserved specimen from Kansas is perhaps a juvenile form with awned leaves and reduced filaments.