[2] These sporangial characters were used by Johann Jakob Bernhardi to define a group of ferns he called the "Cathetogyratae";[3] the Pteridophyte Phylogeny Group has suggested reviving this name as the informal term cathetogyrates, to replace the ambiguously circumscribed term "polypods" when referring to the Polypodiales.

[2] Both Polypodiales and Cyatheales differ from other ferns in having a photoreceptor called a neochrome, which allows them to perform photosynthesis better in low-light conditions, such as in the shadows on the forest floor.

[1] The circumscription of the order has changed over time as ferns have been classified in many different ways (see the review by Christenhusz and Chase, 2014).

[8] They referred to the ferns (now including horsetails) as monilophytes, dividing them into four groups, with the vast majority of species being placed in a taxon they called "Polypodiopsida".

[1] Osmundales Hymenophyllales Gleicheniales Schizaeales Salviniales Cyatheales Polypodiales (6 suborders, 26 families) Despite being the most diverse order of ferns, they appeared relatively late in the evolutionary history of the group, during the Early Cretaceous, and diversified substantially throughout the period.

Christenhusz and Chase in 2014 used a very broad circumscription of Aspleniaceae and Polypodiaceae, reducing families used in other systems to subfamilies.

Smith et al. (2006) divided the Polypodiales into fifteen families,[8] a practice continued in their 2008 revision,[12] with members of the eupolypods placed in two unranked clades.

The circumscription of Lomariopsidaceae changed dramatically, with most historical genera of that family (except Lomariopsis and Thysanosoria) being moved to Dryopteridaceae, while Cyclopeltis and Nephrolepis were added.

In lieu of the expansion of Aspleniaceae and Polypodiaceae, eupolypods I and II were recognized and named as suborders:[1][7] Saccolomataceae Cystodiaceae Lonchitidaceae Lindsaeaceae Pteridaceae Dennstaedtiaceae Cystopteridaceae Rhachidosoraceae Diplaziopsidaceae Desmophlebiaceae Hemidictyaceae Aspleniaceae Thelypteridaceae Woodsiaceae Athyriaceae Onocleaceae Blechnaceae Didymochlaenaceae Hypodematiaceae Dryopteridaceae Nephrolepidaceae Lomariopsidaceae Tectariaceae Oleandraceae Davalliaceae Polypodiaceae Saccolomataceae Cystodiaceae Lonchitidaceae Lindsaeaceae Pteridaceae Dennstaedtiaceae Cystopteridaceae Rhachidosoraceae Diplaziopsidaceae Desmophlebiaceae Hemidictyaceae Aspleniaceae Thelypteridaceae Woodsiaceae Onocleaceae Blechnaceae Athyriaceae Hypodematiaceae Didymochlaenaceae Dryopteridaceae Lomariopsidaceae Nephrolepidaceae Tectariaceae Oleandraceae Davalliaceae Polypodiaceae Now-obsolete families of Polypodiales include: Polypodiales may be regarded as one of the most evolutionarily advanced orders of monilophytes (ferns), based on recent genetic analysis.