Sori submarginal, terminal on veinlets, sts united into coenosori. Indusium attached at base, opening towards lamina margin, sides attached or free. Lamina margin protective, sts thin and indusium-like. Sporangia stalked, dehiscing by transverse slit; annulus incomplete, vertical; spores 32-64, tetrahedral, without perispore. Rhizome slender, bearing narrow paleae, us. protostelic; stipes not jointed to rhizome. Fronds simple to dissected; veinlets free or sts anastomosing; lamina margin thickened and decurrent. About 9 genera, mainly terrestrial, of wide distribution.