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. Phenology: 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.