Nearly worldwide, tropical and subtropical regions.
Genera ca. 16, species ca. 200 (3 genera, 4 species in the flora).
Pterobryaceae are highly diverse, and the family has frequently been the repository of odd, tropical taxa excluded from other families. Few features unite members of the family as currently circumscribed, and even these are not present in all taxa: tropical, primarily epiphytic habitats; a frondose habit, frequently with a differentiated stipe, although this may only be apparent in juvenile plants; 1-seriate, filamentous pseudoparaphyllia (B. H. Allen 1987); absent stomata; reduced peristomes, often with a prostome; and a highly reduced endostome. The inclusion of Henicodium in the family is questionable on morphological grounds, since the presence of papillae centrally located over the lumen and a revolute leaf margin are otherwise not known in Pterobryaceae. Molecular studies indicate some affinity between Henicodium and Orthostichopsis (W. R. Buck et al. 2000), although Pterobryon, the type genus, is usually placed distantly from both these exemplars. Henicodium is accepted here pending resolution of the family circumscription.
|1||Stem leaf margins revolute; alar cells oblate, well differentiated, regions large, conspicuous; medial laminal cells 1-papillose or rarely smooth.||Henicodium|
|1||Stem leaf margins plane; alar cells quadrate or rectangular, little differentiated, indistinct, or regions in several rows along margin; medial laminal cells smooth or prorate||> 2|
|2||Stems simple or sparsely branched; stem leaves broadly ovate-orbicular, spreading to recurved or squarrose; costae double and short, or single to mid leaf or longer.||Jaegerina|
|2||Stems simple or irregularly pinnate; stem leaves broadly ovate-acuminate or ovate-lanceolate, erect or spreading; costae single, short in proximal leaves, percurrent or short-excurrent in distal leaves.||Pireella|