Terrestrial or lithophytic, paroecious or dioicous (not in Victoria). Stems simple or sparingly branched near base, with two ranks of lateral leaves, erect with normal leaves and prostrate with microphylls; branches emerging from near lateral leaves and with a collar of tissue at base. Lateral leaves transverse to succubous, imbricate, especially toward stem apex, contiguous or distant, erect-appressed or loosely spreading (not in Victoria), ovate to orbicular (not in Victoria) in outline, concave, bilobed or unlobed (not in Victoria); lobes entire, rounded or acute. Underleaves completely absent. Leaf cells circular to elliptic or quadrate to oblong (not in Victoria), smooth, thin-walled with distinct trigones or evenly thick-walled (not in Victoria), with 2–4 ovoid to ellipsoid and granular-botryoidal oil bodies, sometimes becoming hyaline and without oil bodies near margins (not in Victoria). Androecia with up to 12 pairs of leaf-like but larger and more ventricose bracts, each with 1–6 antheridia. Sporophyte at apex of leading stem, surrounded by bracts and a highly reduced perianth; bracts similar to normal vegetative lateral leaves but larger; perianth concealed by bracts, terminal on short tubular perigynium, short, tubular or ovoid, plicate and crenulate at mouth, with age sometimes becoming dissected. Capsule spherical to ovoid, 2–3-stratose, barely emergent beyond bracts when fully mature; elaters 2–4-spiral.
Around 26 species, mostly from northern temperate to polar regions, but also in Central America northern and western South America, south-east Asia and Malesia, New Zealand and south-east Australia (Váňa et al. 2010); one species, M. sparsifolia (Lindb.) Dumort., in Victoria.
Váňa, J., Söderström, L., Hagborg, A., von Konrat, M. & Engel, J.J. (2010). Early land plants today: Taxonomy, systematics and nomenclature of Gymnomitriaceae. Phytotaxa 11: 1–80.
