Menyanthaceae 

{{Short description|Family of flowering plants}}

{{Automatic taxobox

|image = Menyanthes_trifoliata_-_Köhler–s_Medizinal-Pflanzen-225.jpg

|image_caption = Menyanthes trifoliata

|taxon = Menyanthaceae

|authority = Dumort.{{Cite journal |last=Angiosperm Phylogeny Group |year=2009 |title=An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG III |journal=Botanical Journal of the Linnean Society |volume=161 |issue=2 |pages=105–121 |doi=10.1111/j.1095-8339.2009.00996.x |doi-access=free |hdl=10654/18083 |hdl-access=free }}

|subdivision_ranks = Genera

|subdivision = See text.

}}

Menyanthaceae is a family of aquatic and wetland plants in the order Asterales. There are approximately 60-70 species in six genera distributed worldwide. The simple or compound leaves arise alternately from a creeping rhizome. In the submersed aquatic genus Nymphoides, leaves are floating and support a lax, umbellate or racemose inflorescence. In other genera the inflorescence is erect and consists of one (e.g., Liparophyllum) to many flowers. The sympetalous, insect-pollinated flowers are five-parted and either yellow or white. The petals are ciliate or adorned with lateral wings. Fruit type is a capsule.

Species of Menyanthaceae are found worldwide. The genera Menyanthes and Nephrophyllidium grow only in the northern hemisphere, while Liparophyllum and Villarsia occur only in the southern hemisphere. Nymphoides species have a cosmopolitan distribution.

Menyanthaceae species are of economic importance as ornamental water garden plants, with Nymphoides being most commonly traded. The practice of growing non-native water plants has led to several species becoming naturalized or invasive.

Dimorphic heterostyly occurs in all genera but Liparophyllum. In addition, four species of Nymphoides are dioecious.{{cite journal|doi=10.1600/036364411X605092|title=Phylogenetic Relationships and Morphological Evolution in Nymphoides (Menyanthaceae)|year=2011|last1=Tippery|first1=Nicholas P.|last2=Les|first2=Donald H.|journal=Systematic Botany|volume=36|issue=4|pages=1101–1113|s2cid=83643283}}