Alismatidae
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Alismatidae
(ə′liz′mad·ə′dē)
(botany) A relatively primitive subclass of aquatic or semiaquatic herbaceous flowering plants in the class Liliopsida, generally having apocarpous flowers, and trinucleate pollen and lacking endosperm.
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Alismatidae
A relatively primitive subclass of the class Liliopsida (monocotyledons) of the division Magnoliophyta (Angiospermae), the flowering plants, consisting of 4 orders, 16 families, and less than 500 species. Typically they are aquatic or semiaquatic, with apocarpous flowers and nonendospermous seeds. They have trinucleate pollen, and the stomates usually have two subsidiary cells. The orders Alismatales, Hydrocharitales, and Najadales are closely related among themselves and have often been treated as a single order, Helobiae or Helobiales. The Triuridales differ from the other orders in being terrestrial and mycotrophic, without chlorophyll, and in having abundant endosperm in the seeds. See also Alismatales; Hydrocharitales; Triuridales; Magnoliophyta; Najadales; Plant kingdom.
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Alismatidae
IN BRIEF: n. - One of four subclasses or superorders of Monocotyledones.
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Alismatidae
Alismatidae is a botanical name at the rank of subclass. Circumscription of the subclass will vary with the taxonomic system 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
- superorder Alismatanae
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 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.
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Mentioned in
Helobiales
(botany)
Hydrocharitales
(botany)
Alismatales
(botany)
Najadales
(botany)
Triuridales
(botany)
» More