The Alismatales comprise herbaceous flowering plants of often aquatic and marshy habitats, and the only monocots known to have green embryos other than the Amaryllidaceae.

Both marine and freshwater forms include those with staminate flowers that detach from the parent plant and float to the surface.

Most aquatic species have a totally submerged juvenile phase, and flowers are either floating or emerge above the water's surface.

[8] 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.

[9] Consequently, the family structure for APG IV is: Araceae Tofieldiaceae Alismataceae Butomaceae Hydrocharitaceae Aponogetonaceae Scheuchzeriaceae Juncaginaceae Maundiaceae Potamogetonaceae Zosteraceae Posidoniaceae Cymodoceaceae Ruppiaceae Cladogram showing the orders of monocots (Lilianae sensu Chase & Reveal)[10] based on molecular phylogenetic evidence: Acorales Alismatales Petrosaviales Dioscoreales Pandanales Liliales Asparagales Dasypogonaceae Arecales Poales Zingiberales Commelinales