Worldwide in tropics and subtropics.
In species outside the flora, leaves may be much shorter and broader with more than one row of areolae and several soral lines on each side of the midrib. Rarely veins are free, and sporangia are scattered over the abaxial surface. Gametophyte gemmae may be much longer than found in the flora, may be platelike, or may be absent.
Vegetative proliferation of gametophytes of this family allows the gametophyte generation to persist after sporophytes are produced. Although sporophytes of only one species, Vittaria lineata, are known in the flora, at least two additional species are represented by persistent gametophytes. Because sporophytes of V. graminifolia may occur in the flora, characteristics of its sporophyte are included in the key to species.
Genera ca. 10, species ca. 100 (1 genus, 3 species in the flora).