Stems of Polypodiaceae range from erect to long-creeping. The fronds are entire, pinnatifid, or variously forked or pinnate. The petioles lack stipules. The scaly rhizomes are generally creeping in nature. Polypodiaceae species are found in wet climates, most commonly in rain forests. In temperate zones, most species tend to be epiphytic or epipetric.
Molecular phylogenic analysis has led to the division of the Polypodiaceae into five subfamiles, and to the inclusion of genera that have at various times been placed in other families, including the Drynariaceae, Grammitidaceae, Gymnogrammitidaceae, Loxogrammaceae, Platyceriaceae, and Pleurisoriopsidaceae. In the list that follows, the taxa shown with the "(=)" prefix are considered to be synonymyms for the accepted subfamily name that they follow. However, this does not necessarily imply that the subfamily contains all of the synonym's previous genera.
^Schuettpelz (2008)[permanent dead link] Schuettpelz & Pryer "Fern pylogeny" in Biology and Evolution of Ferns and Lycophytes], ed. Tom A. Ranker and Christopher H. Haufler. Cambridge University Press 2008