Plants: small to medium-sized, in creeping mats, green to yellowish. Stems: irregularly to regularly pinnate; paraphyllia absent or few, scalelike or squamiform, cells smooth or papillose; rhizoids often arising from base of leaves. Stem: and branch leaves similar. Stem: leaves crisped, incurved to slightly contorted when dry, erect and spreading when moist, ovate, ovate-lanceolate, or lanceolate, not plicate; margins plane, serrate or entire, limbidium sometimes present; apex gradually or abruptly acuminate, hair-point present or absent; costa single, ending before apex, pellucid, straight distally; alar cells not differentiated; medial and distal laminal cells quadrate-hexagonal, oblong, or rhomboidal, finely and obscurely 1- or multipapillose over lumen, walls moderately thick. : Specialized asexual reproduction absent. Sexual: condition dioicous; perichaetial leaves pale translucent, longer, apex more acuminate. Seta: to 2 cm. Capsule: inclined to horizontal, oblong-oval, asymmetric; annulus present; operculum conic- to long-rostrate; peristome well developed; exostome teeth lanceolate, densely cross striate-papillose basally, papillose distally; endostome basal membrane high, segments slender, cilia long. Spores: 9–21 µm, smooth or papillose. w North America, Mexico, w Europe, e Asia, Pacific Islands (Hawaii).
Species 8 (4 in the flora). Claopodium is a genus of small plants with creeping stems, short, papillose laminal cells, pellucid costa, and asymmetric brown capsules with a well-developed peristome. The leaves are broad at the base; the capsules have short necks, are constricted below the mouth when dry, and have bordered exostome teeth and nodose endostome cilia. The genus is somewhat heterogeneous, as C. whippleanum lacks hair-points and superficially is similar to Leskea. Recent phylogenetic work suggests that Claopodium is related to Anomodon (Anomodontaceae).