{{Short description|Genus of ferns}} {{Automatic taxobox | image = Diplazium dietrichianum RBG Sydney.jpg | image_caption = ''Diplazium dietrichianum'' | taxon = Diplazium | authority = Sw.{{R|COL}} | subdivision_ranks = Species | subdivision = See List of ''Diplazium'' species | synonyms = {{Genus list|header=16 synonyms|hidden=yes |Allantodia |Wall. |Allantodia |R.Br. |Anisogonium |C.Presl |Arcasplenium |T.Moore ex Baker |Brachysorus |C.Presl |Callipteridastrum |Fée |Callipteris |Bory |Didymochlamys |T.Moore |Digrammaria |C.Presl |Lotzea |Klotzsch & H.Karst. |Microstegia |C.Presl |Monomelangium |Hayata |Ochlogramma |C.Presl |Oxygonium |C.Presl |Pteriglyphis |Fée |Triblemma |(J.Sm.) Ching }} | synonyms_ref = {{R|COL|PPGI}} }}
'''''Diplazium''''' is a genus of ferns that specifically includes the approximately 400 known species of '''twinsorus ferns'''. The Greek root is ''diplazein'' meaning ''double'': the indusia in this genus lie on '''both sides''' of the vein. These ferns were earlier considered part of either the Athyriaceae, Dryopteridaceae,<ref name="fna" >{{citation | contribution-url = http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=110366 | title = Flora of North America | contribution = 3. Diplazium Swartz }}</ref> Aspleniaceae, or Polypodiaceae families or recognized as belonging to their own taxonomic family. The Pteridophyte Phylogeny Group classification of 2016 (PPG I) places the genus in the Athyriaceae.<ref name=PPGI>{{citation |author=PPG I |title=A community-derived classification for extant lycophytes and ferns |year=2016 |journal=Journal of Systematics and Evolution |volume=54 |issue=6 |pages=563–603 |doi=10.1111/jse.12229|s2cid=39980610 |doi-access=free }}</ref> The taxonomy of the genus is difficult and poorly known, and by 2009 has never been the subject of a complete monographic study.<ref>Leticia Pacheco and Robbin C. Moran. Lectotypification of Several Names Currently Placed in Diplazium (Woodsiaceae). ''American Fern Journal'', Vol. 93, No. 2 (Apr. - Jun., 2003), pp. 90-92</ref> Their distribution is pantropical, with a few species extending into temperate areas.<ref name="fna" /><ref>{{GRIN | ''Diplazium esculentum'' | 403231 | accessdate = 12 January 2018}}</ref>
The rhizome of the genus ''Diplazium'' varies from creeping to erect, and is scaly. Its fronds are deciduous or evergreen, are trophopodic<ref group="nb">The trophopod is food storage organ described from a number of North American ferns. It consists of the enlarged and modified leaf base filled with starch storage tissue. See W. H. Wagner, Jr. and D. M. Johnson, ''Taxon'', Vol. 32, No. 2 (May, 1983), pp. 268-269 for more information on this organ.</ref> and are either monomorphic or weakly dimorphic. The stipe is green, deeply grooved from above, and is either scaly or glabrous. It always has two lunate vascular bundles. The blades are either singular or in sets of two and are entirely pinnate, range from oblong-lanceolate to deltate, and from herbaceous to papery. It has linear basal sori that are paired back-to-back on the same vein. The indusium is linear and persistent, and the sporangia are brownish.
Some common species include ''Diplazium hymenodes'', the peacock fern; ''Diplazium esculentum'', the vegetable fern; ''Diplazium molokaiense'', the Molokai twinsorus fern; and ''Diplazium lonchophyllum'', the lance-leaved glade fern.
==Taxonomy== ''Diplazium'' is in the family Athyriaceae in the eupolypods II clade of the order Polypodiales.<ref name=Christenhusz-2011/><ref name=Smith-2006/> The common glade fern of North America, ''Diplazium pycnocarpon'', is found not to belong to that genus, but rather placed in the genus ''Homalosorus'' (Diplaziopsidaceae).<ref name=Christenhusz-2011/> Two further species formerly placed in the genus have been transferred to a new genus, ''Desmophlebium''.<ref name=MynsVascMoraSylv16>{{Cite journal |last1=Mynssen |first1=Claudine M. |last2=Vasco |first2=Alejandra |last3=Moran |first3=Robbin C. |last4=Sylvestre |first4=Lana S. |last5=Rouhan |first5=Germinal |date=2016 |title=Desmophlebiaceae and ''Desmophlebium'': A new family and genus of Eupolypod II ferns |journal=Taxon |volume=65 |issue=1 |pages=19–34 |url=https://www.researchgate.net/publication/297717881 |accessdate=2019-07-26 |doi=10.12705/651.2 |name-list-style=amp }}</ref>
==Selected species== {{main|List of Diplazium species}} *''Diplazium australe'' *''Diplazium dietrichianum'' *''Diplazium dilatatum'' *''Diplazium esculentum'' *''Diplazium fraxinifolium'' *''Diplazium hymenodes'' *''Diplazium laffanianum'' *''Diplazium melanochlamys'' *''Diplazium molokaiense'' *''Diplazium queenslandicum'' *''Diplazium sibiricum''
== Notes == <references group="nb" />
== References == {{Reflist|refs= <ref name="COL">{{cite web |last1=Bánki |first1=O. |last2=Roskov |first2=Y. |last3=Döring |first3=M. |last4=Ower |first4=G. |last5=Hernández Robles |first5=D.R. |last6=Plata Corredor |first6=C.A. |last7=Stjernegaard Jeppesen |first7=T. |last8=Örn |first8=A. |last9=Pape |first9=T. |last10=Hobern |first10=D. |last11=Garnett |first11=S. |last12=Little |first12=H. |last13=DeWalt |first13=R.E. |last14=Miller |first14=J. |last15=Orrell |first15=T. |last16=Aalbu |first16=R. |last17=Abbott |first17=J. |last18=Aedo |first18=C. |last19=Aescht |first19=E. |url=https://www.catalogueoflife.org/data/taxon/465R |title=''Diplazium'' Sw. |website=Catalogue of Life (Version 2025-09-26) |publisher=Catalogue of Life Foundation, Amsterdam, Netherlands |year=2025 |access-date=26 September 2025}}</ref>
<ref name=Smith-2006>{{cite journal |author1=Alan R. Smith |author2=Kathleen M. Pryer |author3=Eric Schuettpelz |author4=Petra Korall |author5=Harald Schneider |author6=Paul G. Wolf |year=2006 |title=A classification for extant ferns |journal=Taxon |volume=55 |issue=3 |pages=705–731 |url=http://www.pryerlab.net/publication/fichier749.pdf |doi=10.2307/25065646 |jstor=25065646 |url-status=dead |archiveurl=https://web.archive.org/web/20080226232147/http://www.pryerlab.net/publication/fichier749.pdf |archivedate=2008-02-26 }}</ref>
<ref name=Christenhusz-2011>{{cite journal |author1=Maarten J. M. Christenhusz |author2=Xian-Chun Zhang |author3=Harald Schneider |year=2011 |title=A linear sequence of extant families and genera of lycophytes and ferns |journal=Phytotaxa|volume=19|pages=7–54 |doi=10.11646/phytotaxa.19.1.2 |url=http://www.mapress.com/phytotaxa/content/2011/f/pt00019p054.pdf}}</ref> }}
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Category:Diplazium Category:Fern genera Category:Pantropical flora Category:Taxa named by Olof Swartz