Region: North America, Mexico, West Indies, Central America, South America, Eurasia, Africa, Atlantic Islands, Pacific Islands (Hawaii), Pacific Islands (New Zealand), Australia.
Genera: 5; ± 17 species.
BotanyMoss; very small, often in silky mats, green, yellow-green, or gray-green. Stems often erect-ascending, sparsely and irregularly branched, branches terete-foliate, often subjulaceous; radiculose in scattered tufts.
Leaves: ovate to oblong-lanceolate, rarely lanceolate, often somewhat concave; margins plane, denticulate, dentate, or ciliate-dentate, rarely entire; apex acute, acuminate, or long-acuminate, subulate to piliferous, rarely blunt; costa single, 1/3–2/3 leaf length, terminal spine sometimes present, small; alar cells quadrate in several rows; basal laminal cells rounded-rhomboidal to rhomboidal, quadrate to transversely rectangular in few rows along margins; medial and distal cells rhombic, rhomboidal, or elongate-rhombic, 30–45 × 9–12 µm, smooth; apical cells linear.
Specialized asexual reproduction apparently by foliose pseudoparaphyllia. Sexual condition autoicous; seta single, light yellow, erect, smooth.
Capsule: with neck short, wrinkled when old, mouth often flared with age; exothecial cells +- isodiametric, walls sinuate, suboral cells transversely elongate, angular, walls straight; stomata present in neck; annulus absent; operculum conic, umbonate to mammillate; peristome single, rarely absent, erect-spreading, sometimes recurved when dry, incurved when moist; exostome teeth 16, usually connate in pairs, redbrown, broadly lanceolate, blunt, 0.3 mm, densely papillose-striolate; calyptra cucullate.
Spores 9–14 µm, coarsely papillose or smooth.
Genera: Dimerodontium, Fabronia, Ischyrodon, Levierella, Rhizofabronia