Plants: small or minute, green, yellow-green, yellow-brown, or brown. Stems: irregularly branched to pinnate; hyalodermis absent, central strand narrow or absent; paraphyllia absent or few; rhizoids or rhizoid initials on stem or abaxial costa insertion, rarely forming tomentum, slightly or strongly branched, smooth or slightly warty-papillose; axillary hair distal cells 1–6, hyaline. Stem: leaves recurved or squarrose, sometimes slightly homomallous, cordate or narrowly to broadly ovate, not or near base slightly plicate, to 1 mm; base decurrent or not; margins plane or near base recurved, denticulate or entire, limbidia absent; apex acuminate or narrowly so, acumen furrowed; costa double, short, distal abaxial surface sometimes rough or terminal spine present; alar cells differentiated, small, region distinctly or indistinctly delimited, quadrate, isodiametric, oblong, or broadly ovate, along margin; medial laminal cells elongate-hexagonal to linear; distal cells sometimes prorate distally on dorsal side; marginal cells 1-stratose. Sexual: condition autoicous. Capsule: ± horizontal, cylindric, ± curved; peristome perfect; exostome margins dentate or slightly dentate distally; endostome cilia 1–3, well developed, nodose. Spores: 8–18(–21) µm. North America, Mexico, South America, Eurasia.
Species 10 or 11 (3 in the flora). Campylophyllum grows on at least periodically dry calcareous rock and soil, or on organic substrates. In size and microscopic features, Campylophyllum is similar to certain Hypnum species, such as H. pallescens and H. recurvatum, rather than to species of Campyliadelphus or Campylium despite striking differences in leaf orientation.