Dryopteridaceae
The Dryopteridaceae are a family of leptosporangiate ferns in the order Polypodiales. They are known colloquially as the wood ferns. In the Pteridophyte Phylogeny Group classification of 2016 (PPG I), the family is placed in the suborder Polypodiineae. Alternatively, it may be treated as the subfamily Dryopteridoideae of a very broadly defined family Polypodiaceae "sensu lato". The family contains about 1700 species and has a cosmopolitan distribution. Species may be terrestrial, epipetric, hemiepiphytic, or epiphytic. Many are cultivated as ornamental plants. The largest genera are "Elaphoglossum" (600+), "Polystichum" (260), "Dryopteris" (225), and "Ctenitis" (150). These four genera contain  about 70% of the species. Dryopteridaceae diverged from the other families in eupolypods I about 100 million years ago. Description. The rhizomes are often stout, creeping, ascending, or erect, and sometimes scandent or climbing, with nonclathrate scales at apices. Fronds are usually monomorphic, less often dimorphic, or sometimes scaly or glandular, but less commonly hairy. Petioles have numerous round, vascular bundles arranged in a ring, or rarely as few as three; the adaxial bundles are largest. Veins are pinnate or forking, free to variously anastomosing; the areoles occur with or without included veinlets; sori are usually round, acrostichoid (covering the  entire abaxial surface of the lamina) in a few lineages; usually indusiate, or sometimes exindusiate. Indusia, when present, are round-reniform or peltate. Sporangia have three-rowed, short to long stalks; spores arereniform, monolete, perine or winged. Taxonomy. History. In 1990, Karl U. Kramer and coauthors defined the Dryopteridaceae broadly to include the present family, as well as the Woodsiaceae "sensu lato", Onocleaceae, and most of Tectariaceae. Molecular phylogenetic studies found Kramer's version of the Dryopteridaceae to be polyphyletic, and it was split up by Smith and others in 2006. The inclusion of "Didymochlaena", "Hypodematium", and "Leucostegia" in the  Dryopteridaceae is doubtful. If these three are excluded, then the family is strongly supported as monophyletic in cladistic analyses. Some authors have already treated these genera as outside of the Dryopteridaceae. In 2007, a phylogenetic study of DNA sequences showed that "Pleocnemia" should be transferred from the Tectariaceae to the Dryopteridaceae. In 2010, in a paper on bolbitidoid ferns, "Arthrobotrya" was resurrected from "Teratophyllum". Later that year, "Mickelia" was described as a new genus. Some species have been removed from the genus "Oenotrichia" because they do not belong there or even in the family Dennstaedtiaceae where "Oenotrichia" "sensu stricto" is  placed. These species probably belong in the Dryopteridaceae, but have not yet been given a generic name. In 2012, a phylogenetic study of "Dryopteris" and its relatives included "Acrophorus", "Acrorumohra", "Diacalpe", "Dryopsis", "Nothoperanema", and "Peranema" within that genus. The "Flora of China" treatment of the family, published in 2013, used phylogenetic results to sink "Lithostegia" and "Phanerophlebiopsis" into "Arachniodes". The Dryopteridaceae , under the classification system of Christenhusz and Chase (2014), were submerged as subfamily Dryopteridoideae , one of eight subfamilies constituting family Polypodiaceae. This family corresponds to the clade eupolypods I. The Pteridophyte Phylogeny Group classification of 2016 (PPG I) retained  the family. Phylogeny. The following cladogram for the suborder Polypodiineae (eupolypods I), based on the consensus cladogram in the Pteridophyte Phylogeny Group classification of 2016 (PPG I), shows a likely phylogenetic relationship between Dryopteridaceae and the other families of the clade. Subdivision. The PPG I classification divides the family into three subfamilies, listed below. "Didymochlaena" has been removed to Didymochlaenaceae, and "Hypodematium" and "Leucostegia" to Hypodematiaceae. "Aenigmopteris" has at times been suggested to belong to this family, on the grounds of its morphological similarity to "Ctenitis", but molecular phylogeny has led to its submersion within "Tectaria" (Tectariaceae). "Dryopolystichum" has been  placed in Lomariopsidaceae.