Editing Alismatales (section)

==Taxonomy==
The Alismatales contain about 165 genera in 13 families, with a [[cosmopolitan distribution]]. [[Phylogenetically]], they are [[basal monocot]]s, diverging early in evolution relative to the [[lilioid]] and [[commelinid]] [[monocot]] lineages.{{sfn|Wilkin|Mayo|2013}} Together with the [[Acorales]], the Alismatales are referred to informally as the alismatid monocots.{{sfn|RBG|2010}}

===Early systems===
The [[Cronquist system]] (1981) places the Alismatales in subclass [[Alismatidae]], class [[Liliopsida]] [= monocotyledons] and includes only three families as shown:
* [[Alismataceae]]
* [[Butomaceae]]
* [[Limnocharitaceae]]
Cronquist's subclass Alismatidae conformed fairly closely to the order Alismatales as defined by APG, minus the Araceae.

The [[Dahlgren system]] places the Alismatales in the superorder [[Alismatanae]] in the subclass [[Liliidae]] [= monocotyledons] in the class [[Magnoliopsida]] [= angiosperms] with the following families included:
*  [[Alismataceae]]
*  [[Aponogetonaceae]]
*  [[Butomaceae]]
*  [[Hydrocharitaceae]]
*  [[Limnocharitaceae]]

In Tahktajan's classification (1997), the order Alismatales contains only the Alismataceae and Limnocharitaceae, making it equivalent to the Alismataceae as revised in APG-III. Other families included in the Alismatates as currently defined are here distributed among 10 additional orders, all of which are assigned, with the following exception, to the Subclass Alismatidae. Araceae in Tahktajan 1997 is assigned to the [[Arales]] and placed in the Subclass Aridae; Tofieldiaceae to the [[Melanthiales]] and placed in the [[Liliidae]].<ref>{{cite web| url = http://botany.csdl.tamu.edu/FLORA/newgate/cronang.htm| title = -Flowering Plant Gateway| access-date = 27 May 2010| archive-date = 6 October 2011| archive-url = https://web.archive.org/web/20111006041129/http://botany.csdl.tamu.edu/FLORA/newgate/cronang.htm| url-status = dead}}</ref>

===Angiosperm Phylogeny Group===
The Angiosperm Phylogeny Group system ([[APG system|APG]]) of 1998 and [[APG II system|APG II]] (2003) assigned the Alismatales to the monocots, which may be thought of as an unranked clade containing the families listed below. The biggest departure from [[list of systems of plant taxonomy|earlier 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, totaling over two thousand species. The rest of the families together contain only about five hundred species, many of which are in very small families.{{sfn|APG IV|2016}}

The [[APG III system]] (2009) differs only in that the [[Limnocharitaceae]] are combined with the Alismataceae; it was also suggested that the genus ''[[Maundia]]'' (of the [[Juncaginaceae]]) could be separated into a monogeneric family, the [[Maundiaceae]], but the authors noted that more study was necessary before the Maundiaceae could be recognized.<ref name="apgiii" />

* order Alismatales ''[[sensu]]'' APG III
*: family [[Alismataceae]] (''including'' [[Limnocharitaceae]])
*: family [[Aponogetonaceae]]
*: family [[Araceae]]
*: family [[Butomus|Butomaceae]] <!-- monogeneric family -->
*: family [[Cymodoceaceae]]
*: family [[Hydrocharitaceae]]
*: family [[Juncaginaceae]]
*: family [[Posidoniaceae]]
*: family [[Potamogetonaceae]]
*: family [[Ruppiaceae]]
*: family [[Scheuchzeriaceae]]
*: family [[Tofieldiaceae]]
*: family [[Zosteraceae]]

In [[APG IV]] (2016), it was decided that evidence was sufficient to elevate ''Maundia'' to family level as the [[monogeneric]] Maundiaceae.{{sfn|APG IV|2016}} The authors considered including a number of the smaller orders within the Juncaginaceae, but an online survey of botanists and other users found little support for this "[[lumping]]" approach.{{sfnp|ps=none|Christenhusz|Vorontsova|Fay|Chase|2015}} Consequently, the family structure for APG IV is:

{{cladogram
|title=Cladogram of Alismatales<ref name=Stevens />
|{{clade|style=font-size:80%;line-height:100%;width:300px;
|label1='''Alismatales'''
|1={{clade
  |1=[[Araceae]]
  |2={{clade
    |1=[[Tofieldiaceae]]
    |2={{clade
      |1={{clade
        |1=[[Alismataceae]]
        |2={{clade
          |1=[[Butomaceae]]
          |2=[[Hydrocharitaceae]]
           }}
         }}
      |2={{clade
        |1=[[Aponogetonaceae]]
        |2={{clade
          |1=[[Scheuchzeriaceae]]
          |2={{clade
            |1=[[Juncaginaceae]]
            |2={{clade
              |1=[[Maundiaceae]]
              |2={{clade
                |1={{clade
                  |1=[[Potamogetonaceae]]
                  |2=[[Zosteraceae]]
                   }}
                |2={{clade
                  |1=[[Posidoniaceae]]
                  |2={{clade
                    |1=[[Cymodoceaceae]]
                    |2=[[Ruppiaceae]]
                     }}
                   }}
                 }}
               }}
             }}
           }}
         }}
       }}
     }}
   }}
}}
}}

*: family [[Alismataceae]] (''including'' [[Limnocharitaceae]])
*: family [[Aponogetonaceae]]
*: family [[Araceae]]
*: family [[Butomus|Butomaceae]] <!-- monogeneric family -->
*: family [[Cymodoceaceae]]
*: family [[Hydrocharitaceae]]
*: family [[Juncaginaceae]]
*: family [[Maundiaceae]]
*: family [[Posidoniaceae]]
*: family [[Potamogetonaceae]]
*: family [[Ruppiaceae]]
*: family [[Scheuchzeriaceae]]
*: family [[Tofieldiaceae]]
*: family [[Zosteraceae]]

=== Phylogeny ===
[[Cladogram]] showing the orders of monocots ([[Lilianae]] ''[[sensu]]'' Chase & Reveal){{sfn|Chase|Reveal|2009}} based on molecular phylogenetic evidence:

{{barlabel|size=12|at1=5|label1=[[Lilioid monocots]] |bar1=purple|at2=0.5|label2=Alismatid monocots|bar2=green|style=font-size:100%;line-height:125%;width:400px;|cladogram=
{{clade
|align=center
|label1= [[Lilianae]] ''sensu'' Chase & Reveal{{sfn|Chase|Reveal|2009}} 
|1={{clade
    | 1={{clade|thickness=3
      | 1=[[Acorales]]|barbegin1=green
      | 2={{clade|thickness=3
        |label1=
        | 1= '''Alismatales''' |barend1=green
        | 2={{clade
          | 1=[[Petrosaviales]] |barbegin1=purple
          |2={{clade
            |1={{clade
              |1=[[Dioscoreales]]|bar1=purple
              |2=[[Pandanales]] |bar2=purple
                }}
            | 2={{clade
              |1=[[Liliales]] |bar1=purple
              |2={{clade
                |1=[[Asparagales]] |barend1=purple
                |label2=[[commelinids]]
                |2={{clade
                  |1=[[Dasypogonaceae]]
                  |2=[[Arecales]]
                  |3=[[Poales]]
                  |4={{clade
                    |1=[[Zingiberales]]
                    |2=[[Commelinales]]
                     }}
                   }}
                 }}
               }}
             }}
           }}
         }}
       }}
     }}
}}
}}

{{clear}}