Alismatidae

Alismatidae is a botanical name at the rank of subclass. of the subclass will vary with the being used (there are many such systems); the only requirement being that it includes the family Alismataceae. It is a relatively new name: earlier systems, such as the Engler and Wettstein systems, used the name Helobiae for a comparable unit.

Alismatidae in the Takhtajan system

The Takhtajan system treats this as one of six subclasses within the class Liliopsida (=monocotyledons). It consists of:

* subclass Alismatidae
*: superorder Alismatanae
*:: order Butomales
*:: order Hydrocharitales
*:: order Najadales
*:: order Alismatales
*:: order Aponogetonales
*:: order Juncaginales
*:: order Potamogetonales
*:: order Posidoniales
*:: order Cymodoceales
*:: order Zosterales

Alismatidae in the Cronquist system

The Cronquist system treats this as one of four subclasses within the class Liliopsida (=monocotyledons). It consists of (1981):

* subclass Alismatidae
*: order Alismatales
*: order Hydrocharitales
*: order Najadales
*: order Triuridales

This subclass comprises less than five hundred species total: many of these are aquatic or semiaquatic plants (see [http://www.accessscience.com/Encyclopedia/0/02/Est_022600_frameset.html?doi Alismatidae info] ).

APG II system

The APG II system does not use formal botanical names above the rank of order; it assigns most of the plants involved to the (expanded) order Alismatales, in the clade 'monocots', although the plants in Cronquist's order Triuridales are assigned to quite different placements.