The APG II system, of 2003 (unchanged from the APG system, of 1998) places the family in the order Commelinales, in the commelinid clade, in the monocots. It is a small family of heterostylous aquatic plants, occurring in tropical and subtropical waters. Charles Darwin was interested in the specialized form of heterostyly found in the family, known as tristyly. Not all of the species are heterostylous. The family probably contains fewer than three dozen species.
It is best known for the water hyacinth (Eichhornia crassipes), which is an invasive species in many waterways. The highly modified Hydrothrix gardneri is a submerged aquatic with a two-flowered pseudanthium.
There are 9 genera within this family as below.
- Eichhornia Kunth
- Heteranthera Ruiz & Pav.
- Monochoria C.Presl
- Pontederia L.
- Scholleropsis H.Perrier
- Angiosperm Phylogeny Group (2009). "An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG III" (PDF). Botanical Journal of the Linnean Society 161 (2): 105–121. doi:10.1111/j.1095-8339.2009.00996.x. Retrieved 2013-06-26.
- Pontederiaceae in L. Watson and M.J. Dallwitz (1992 onwards).
- The families of flowering plants: descriptions, illustrations, identification, information retrieval. Version: 9 March 2006. http://delta-intkey.com.
- Pontederiaceae in the Flora of North America
- Pontederiaceae in the Flora of China
- NCBI Taxonomy Browser
- links at CSDL