Pteridaceae is a family of ferns in the order Polypodiales., including some 1150 known species in ca 45 genera (depending on taxonomic opinions), divided over five subfamilies. Members of the family have creeping or erect rhizomes and are mostly terrestrial or epipetric (growing on rock). The leaves are almost always compound and have linear sori that are typically on the margins of the leaves and lack a true indusium, typically being protected by a false indusium formed from the reflexed margin of the leaf. The family includes four groups of genera that are sometimes recognized as separate families: the adiantoid, cheilanthoid, pteroid, and hemionitidoid ferns. Relationships among these groups remain unclear, and although some recent genetic analyses of the Pteridales suggest that neither the family Pteridaceae nor the major groups within it are all monophyletic, as yet these analyses are insufficiently comprehensive and robust to provide good support for a revision of the order at the family level.
As traditionally defined, the groups within Pteridaceae are as follows:
Adiantoid ferns (tribe Adianteae Gaudich. 1829); epipetric, terrestrial or epiphytic in moist habitats, rachis often dichotomously branching; sori relatively small and discrete with sporangia born on the false indusium rather than the leaf blade proper; only one genus:
Adiantum L. – maidenhair ferns
Cheilanthoid ferns; primarily epipetric in semiarid habitats; leaves mostly with well-developed scales or trichomes, often bipinnate or otherwise highly compound; sporangia mostly born in marginal sori with false indusia that are +/- continuous around the leaf margins; several genera, including:
Argyrochosma (J.Sm.) Windham – false cloak ferns
Aspidotis (Nutt. ex Hook.) Copel. – lace ferns
Astrolepis D.M.Benham & Windham – cloak ferns
Cheilanthes Sw. – lip ferns
Notholaena R.Br. – cloak ferns
Pellaea Link – cliff brakes
Pteridoid ferns (tribe Pterideae J. Sm 1841); terrestrial and epipetric in moist habitats; leaves mostly without prominent scales or trichomes, most often pinnate but sometimes more compound; sporangia born in marginal sori with false indusia that are +/- continuous around the leaf margins; several genera, including:
Pteris L. – brakes
Onychium Kaulf.
Parkerioid ferns (tribe Parkerieae Brongn. 1843); aquatic in swamps and/or mangroves, including:
Acrostichum L. – leather ferns
Ceratopteris Brongn.
Hemionitidoid ferns; terrestrial, epipetric or epiphytic in moist or semiarid habitats; leaves simple, pinnate, or more compound; sporangia born in linear non-marginal, exindusiate sori or sometimes in marginal sori; several genera, including:
Anogramma Link
Cryptogramma R.Br. – rock brakes
Eriosorus Fée
Hemionitis L.
Jamesonia Hook. & Grev.
Pityrogramma Link – gold ferns
Vittarioid ferns (tribe Vittarieae C. Presl 1836); primarily epiphytic in tropical regions and all have simple leaves with sori that follow the veins and lack true indusia:
Anetium Splitg. 1840
Antrophyum Kaulf. 1875
Hecistopteris (L.) Sm. 1842
Monogramma Comm. ex Schkuhr 1809
Vittaria (L.) Sm. 1793 – Shoestring fern
Based on phylogenetic research, Christenhusz et al. (2011) divided the Pteridaceae genera into the following subfamilies. These roughly correspond with the groups listed above, with the main difference being that adiantoid and vittarioid ferns are combined under the Vittarioideae subfamily name.
Cryptogrammoideae S.Linds. 2009
Genera:
Coniogramme,
Cryptogramma,
Llavea
Ceratopteridoideae (J.Sm.) R.M.Tryon 1986
Genera:
Acrostichum,
Ceratopteris
Pteridoideae C.Chr. ex Crabbe, Jermy & Mickel 1975
Genera:
Actiniopteris,
Anogramma,
Austrogramme,
Cerosora,
Cosentinia,
Jamesonia (incl.
Eriosorus and
Nephopteris),
Onychium,
Pityrogramma,
Pteris (incl.
Neurocallis &
Platyzoma),
Pterozonium,
Syngramma,
Taenitis,
Tryonia
Cheilanthoideae W.C.Shieh 1973
Genera:
Adiantopsis,
Aleuritopteris,
Allosorus,
Argyrochosma,
Aspidotis,
Astrolepis,
Bommeria,
Calciphilopteris,
Cheilanthes,
Cheiloplecton,
Doryopteris,
Gaga,
Hemionitis,
Lytoneuron,
Mildella,
Myriopteris,
Notholaena,
Ormopteris,
Paragymnopteris,
Parahemionitis,
Pellaea,
Pentagramma,
Trachypteris
Vittarioideae (C.Presl) Crabbe, Jermy & Mickel 1975
Genera:
Adiantum,
Ananthacorus,
Antrophyopsis,
Antrophyum,
Haplopteris,
Hecistopteris,
Polytaenium,
Radiovittaria,
Rheopteris,
Scoliosorus,
Vaginularia,
Vittaria
The following phylogram, showing the relationships between the subfamilies listed above, is based on Schuettpelz & Pryer (2008).
