a small family of ferns (fern) in the division Pteridophyta (the lower vascular plants (plant)). The single genus, Plagiogyria (15 species), is confined to tropical and warm temperate regions from North America to South America and Asia to New Guinea. The species superficially resemble some groups of Blechnaceae, but they are currently thought to be more closely related to the tree ferns (Cyatheaceae and allied families). They are terrestrial and have short, stout rhizomes (rhizome) bearing a cluster of leaves at the tip. The pinnately compound leaves are dimorphic, with the fertile ones having very narrow leaflets that are almost entirely covered with sporangia on the undersurface. The spores are more or less globose (tetrahedral).