What is "grammitid"

The "grammitid ferns" form a clade of about 750 species within the Polypodiaceae. They are distributed over higher elevations in both the Old and New World. This group was previously treated as a separate family ( Grammitidaceae), but because molecular phylogeny showed that it was nested within Polypodiaceae, it is now treated as an informal clade within that family. In 2011, Christenhusz et al. placed the grammitid ferns in the subfamily Polypodioideae, within the Polypodiaceae. The following phylogram shows a likely relationship between grammitid ferns and the Polypodiaceae subfamilies, based on Schuettpelz & Pryer, 2008.