Plants small, in wiry wefts, prostrate mats, or threadlike, dark or olive green to yellowish. Stems erect to ± creeping, freely and irregularly branched to subpinnate; paraphyllia few or absent; pseudoparaphyllia foliose. Leaves erect to erect-spreading or occasionally squarrose, often homomallous, usually imbricate, concave, stem leaves often somewhat larger than branch leaves; margins entire, serrulate, or subentire; apex usually acuminate; ecostate or costa single, double, or 2-fid, short or to mid leaf; alar cells not or weakly differentiated; medial laminal cells quadrate, rhomboidal, or oblong-rhomboidal, smooth or papillose. Sexual condition dioicous. Capsule erect or horizontal, short-cylindric; operculum short-rostrate or conic, cucullate; peristome double.
Nearly worldwide, temperate and tropical regions.
Genera 6, species 28 (4 genera, 8 species in the flora).
Five of the genera of Pterigynandraceae are restricted to the Northern Hemisphere, including all genera found in the flora area. The one exception, Trachyphyllum A. Gepp, is widely distributed in tropical and subtropical areas throughout Africa, central parts of South America, and southern Asia.
|1||Leaf apices long-piliferous; ecostate or occasionally costae double, short; margins entire.||Iwatsukiella|
|1||Leaf apices obtuse, acute, apiculate, or acuminate; costae single, double, or 2-fid, short, to mid leaf, or almost ecostate; margins serrulate, serrate, or dentate||> 2|
|2||Leaves oblong-elliptic; laminal cells oblong-rhombic, prorulose; capsules erect.||Pterigynandrum|
|2||Leaves ovate to broadly ovate; laminal cells quadrate or rhomboidal, papillose, prorulose, or smooth; capsules erect to horizontal||> 3|
|3||Costae single, short, usually 2-fid, or double to mid leaf; capsules horizontal, short- cylindric, curved.||Heterocladium|
|3||Costae short, usually double or indistinct; capsules erect to nearly horizontal, cylindric, symmetric.||Myurella|