Description from Flora of China
Plants terrestrial, rarely epiphytic, generally small, erect, rarely large and pendulous. Rhizome erect, rarely creeping, short, glabrous or long hairy. Fronds often solitary, occasionally 2, rarely more; sterile lamina with stipe, usually simple, lanceolate, ovate, or ribbon-shaped, rarely dichotomously divided, with entire or wavy margin; midrib indistinct; veins reticulate; sporophore arising from base, near base, or middle part of sterile lamina, with long stalk. Sporangia embedded in 2 rows along margin of linear spike; spore surface irregularly reticulate, foveolate, or subsmooth.
About 28 species: mainly in the N Hemisphere; nine species (two endemic) in China.
(Authors: Liu Quanru (刘全儒); Norio Sahashi)