Small epiphytic, lithophytic or terrestrial ferns. Rhizome creeping, narrow or wiry, rarely stout. Lamina simple or pinnately divided, with single vein; margins entire or with minute teeth, glabrous. Sori terminal on ultimate segments or on rows of 1–3 short branchlets on upper side of each secondary rachis; indusium divided to middle or base, sometimes forming tube for part of length, lips toothed or smooth. Receptacle included or very slightly exserted. Sporangia large.
Some 200 species world-wide; 19 in Australia, 5 in Victoria. Hymenophyllum dilatatum (G. Forst.) Sw., a large New Zealand species, was tentatively reported from Victoria by Willis (1970, as Mecodium dilatatum (G. Forst.) Copel.), but it is highly probable that the one herbarium specimen from Australia (allegedly from Cumberland Gorge, Marysville) was incorrectly labelled (Wakefield 1975).