Worldwide, mostly tropical.
The family is variously circumscribed, in the strict sense including only eight genera, while in the broadest sense encompassing about half the recognized genera of higher ferns (R. E. Holttum 1947). Here it is delimited in the sense of J. T. Mickel (1973). Characteristics that define the family include submarginal or marginal sori with generally two indusia, an inner true indusium and an outer false indusium formed by the revolute, often modified segment margin (although either type may be reduced or absent in some genera); indument usually of hairs rather than scales; and long-creeping protostelic or solenostelic stems with stem buds on the bases of the petioles. Not all genera in the family share all the characteristics.
Genera ca. 20, species perhaps 400 (4 genera, 6 species in the flora).
|1||Sori continuous along margins of segments; inner indusium, if present, hidden by reflexed margin of blade and maturing sporangia; blades usually broadly triangular.||Pteridium|
|1||Sori distinct, not continuous along margins of ultimate segments; inner indusium present or absent; blades narrowly deltate to lanceolate to ovate.||> 2|
|2||Sori at tips of ultimate segments; veins dichotomously forked.||Odontosoria|
|2||Sori lateral on ultimate segments; veins pinnately branched.||> 3|
|3||Inner indusium absent, outer indusium recurved over sori.||Hypolepis|
|3||Inner indusium present, outer indusium fused with inner one to form cup or tubular structure containing sporangia.||Dennstaedtia|