Alismatidae is a botanical name at the rank of subclass.
The Takhtajan system treats this as one of six subclasses within the class Liliopsida (=monocotyledons).
It consists of: The Cronquist system treats this as one of four subclasses within the class Liliopsida (=monocotyledons).
It consists of (1981): This subclass comprises less than five hundred species total: many of these are aquatic or semiaquatic plants (see Alismatidae info).
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.