{{Taxobox
| color = lightgreen
| name = Alismatales
| image = AlismaPlant1.jpg
| image_width = 240px
| image_caption = ''[[Alisma plantago-aquatica]]''
| regnum = [[Plant]]ae
| divisio = [[Flowering plant|Magnoliophyta]]
| classis = [[Monocotyledon|Liliopsida]]
| ordo = '''Alismatales'''
| ordo_authority = [[Barthélemy Charles Joseph du Mortier|Dumort.]]
| subdivision_ranks = Families
| subdivision = See text
}}

'''Alismatales''' is an order of [[flowering plant]]s. The order will of necessity contain the family [[Alismataceae]].

==Taxonomy==
The [[APG II system]], of 2003 (unchanged from the [[APG system]], of 1998) assigns the order to the clade [[monocots]] and uses this circumscription:
* order Alismatales
*: family [[Alismataceae]]
*: family [[Aponogetonaceae]]
*: family [[Araceae]]
*: family [[Butomaceae]]
*: family [[Cymodoceaceae]]
*: family [[Hydrocharitaceae]]
*: family [[Juncaginaceae]]
*: family [[Limnocharitaceae]]
*: family [[Posidoniaceae]]
*: family [[Potamogetonaceae]]
*: family [[Ruppiaceae]]
*: family [[Scheuchzeriaceae]]
*: family [[Tofieldiaceae]]
*: family [[Zosteraceae]]

Thus circumscribed, the order contains about 165 genera in 14 families, with a [[cosmopolitan distribution]]. Most of the families are composed of [[herbaceous]] plants, commonly found in aquatic environments. The [[flower]]s are usually arranged in [[inflorescence]]s, and the mature seeds lack [[endosperm]].

The biggest departure from earlier [[list of systems of plant taxonomy|systems]] (see below) is the inclusion of family [[Araceae]]. By its inclusion the order has grown enormously in number of species. The family Araceae alone accounts for about a hundred genera, totalling over two thousand species. The rest of families together contain just about five hundred species.

The [[Cronquist system]] of 1981 placed the order in subclass [[Alismatidae]] of class [[Liliopsida]] [= monocotyledons] and used this circumscription:
* order Alismatales
*: family [[Alismataceae]]
*: family [[Butomaceae]]
*: family [[Limnocharitaceae]]
The Cronquist subclass [[Alismatidae]] conformed fairly closely to the order Alismatales as circumscribed by APG, minus the family Araceae.

The [[Dahlgren system]] placed the order in the superorder [[Alismatanae]] in the subclass [[Liliidae]] [= monocotyledons] in the class [[Magnoliopsida]] [= angiosperms]; it used this circumscription:
* order Alismatales
*: family [[Alismataceae]]
*: family [[Aponogetonaceae]]
*: family [[Butomaceae]]
*: family [[Hydrocharitaceae]]
*: family [[Limnocharitaceae]]
The Dahlgren superorder Alismatanae conformed fairly closely to the order Alismatales as circumscribed by APG, minus the family Araceae.

The [[Wettstein system]], last version in 1935, and the [[Engler system]], update in 1964, used the name [[Helobiae]] for the order.

== References ==
* {{cite book| author = [[Barthélemy Charles Joseph du Mortier|B. C. J. du Mortier]] |year = 1829 | title =Analyse des Familles de Plantes : avec l'indication des principaux genres qui s'y rattachent| publisher = Imprimerie de J. Casterman, Tournay}}
* {{cite book | author = W. S. Judd, C. S. Campbell, E. A. Kellogg, P. F. Stevens, M. J. Donoghue | year = 2002 | title = Plant Systematics: A Phylogenetic Approach, 2nd edition | publisher = Sinauer Associates, Sunderland, Massachusetts}} ISBN 0-87893-403-0.

==External links==
* [http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Undef&id=16360&lvl=3&lin=f&keep=1&srchmode=1&unlock NCBI Taxonomy Browser]
{{commonscat|Alismatales}}

[[Category:Alismatales| ]]

[[ca:Alismatal]]
[[da:Skeblad-ordenen]]
[[de:Froschlöffelartige]]
[[es:Alismatales]]
[[fr:Alismatales]]
[[it:Alismatales]]
[[he:כף צפרדע]]
[[la:Alismatales]]
[[lt:Dumblialaiškiečiai]]
[[hu:Hídőrvirágúak]]
[[nl:Alismatales]]
[[ja:オモダカ目]]
[[no:Alismatales]]
[[pl:Żabieńcowce]]
[[pt:Alismatales]]
[[ru:Частухоцветные]]
[[fi:Alismatales]]
[[sv:Alismatales]]
[[vi:Bộ Trạch tả]]
[[zh:澤瀉目]]