Alismatales

Alismatales
Alisma plantago-aquatica
Scientific classification
Kingdom: Plantae Division: Magnoliophyta Class: Liliopsida Order: Alismatales Dumort.
Families
See text

Alismatales is an order of flowering plants. The order will of necessity contain the family Alismataceae.

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 flowers are usually arranged in inflorescences, and the mature seeds lack endosperm.

The biggest departure from earlier systems (see below) is the inclusion of family Araceae. By its inclusion the order has grow 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

• B. C. J. du Mortier (1829). Analyse des Familles de Plantes : avec l'indication des principaux genres qui s'y rattachent. Imprimerie de J. Casterman, Tournay. 
• W. S. Judd, C. S. Campbell, E. A. Kellogg, P. F. Stevens, M. J. Donoghue (2002). Plant Systematics: A Phylogenetic Approach, 2nd edition. Sinauer Associates, Sunderland, Massachusetts.  ISBN 0-87893-403-0.

External links

• NCBI Taxonomy Browser

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Alismatales

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