| Polypodiaceae, Polypodiales, Leptosporangiate fern, Aglaomorpha, Neocheiropteris|
Polypodioideae is a subfamily belonging to the fern family Polypodiaceae. The subfamily name Polypodioideae has two recent uses. The first by Mabberley, 2008, included a larger group of polygrams, (said to possess scales and/or hairs; never stellate), which included six tribes, one of which, Polypodieae, is considered to be a synonym of the more recent sense of Polypodioideae by Christenhusz et al., 2011, in which Polypodiaceae contains five subfamilies, including the smaller Polypodioideae subfamily.
Mabberley, in 2008, defined this subfamily in a very broad sense, including all of Polypodiaceae except for the Platycerioideae (Platycerium and Pyrrosia) and the grammitid ferns, which he placed in Grammitidaceae. He distinguished this subfamily from the platycerioids by the absence of stellate hairs on the fronds. He subdivided it into six tribes, Drynarieae (fronds dimorphic; Aglaomorpha and Drynaria), Selligueeae (fronds monomorphic, with opaque scales on the stem; Selliguea), Lepisoreae (fronds monomorphic, with clathrate scales and thick exospore; Belvisia and Lepisorus), Microsoreae (fronds monomorphic, with clathrate scales and thin exospore), Polypodieae (Pecluma and Polypodium), and Loxogrammeae (lacking internal sclerenchyma above roots; Loxogramme).
Christenhusz et al., in 2011, incorporated phylogenetic evidence to recircumscribe the family, combining the grammitids with Mabberley's Polypodieae (recognizing a number of segregate genera). The classification of Christenhusz and Chase in 2014 vastly expanded the circumscription of Polypodiaceae; it redefined Polypodioideae to include all of what had generally been theretofore recognized as Polypodiaceae, including the grammitids. The authors recognized five tribes in this expanded circumscription: Loxogrammeae, Drynariae (including both drynarioid and selligueoid ferns), Platycerieae (platycerioids), Microsoreae (including Mabberley's Lepisoreae), and Polypodieae, the last corresponding to Polypodioideae in Christenhusz et al.
The most recent circumscription of the subfamily, the PPG I classification, largely returns to that of Christenhusz et al., but excludes the grammitids as subfamily Grammitoideae, rendering the Polypodioideae paraphyletic.
The following phylogram shows a likely relationship between Polypodioideae and the other subfamilies within Polypodiaceae, based on groups described by Schuettpelz & Pryer, 2008, using the subfamily names of Christenhusz et al., 2011.
The following grouping of Polypodioideae genera is based on Christenhusz et al., 2011.
(includes family Grammitidaceae)