Filmy Ferns

Mostly epiphytic (some terrestrial or epilithic) ferns. Rhizome widely creeping to short and suberect, slender, irregularly branched, also with short adhesive hairs. Fronds monomorphic, widely spaced or approximate, arranged in 1 row or tufted. Stipe with a single circular stele; obsolete or distinct, narrowly winged distally or along the entire length. Lamina simple or divided, exceptionally thin (1 cell thick) and delicate, ultimate segments one-veined; rhachis winged or not; venation free. Sporangia borne on slender receptacle within tubular cup-shaped or deeply 2-cleft indusium, homosporus, spores green.