POTAMOGETONACEAE (Pondweed Family)

One or 2 genera, about 90 species, worldwide.

The circumscription of the Potamogetonaceae has undergone revision during the past few decades. The family, as traditionally circumscribed, includes genera here treated in the Najadaceae, Ruppiaceae, and Zannichelliaceae. Some authors continue to place various of these groups, particularly the genus Ruppia, into the Potamogetonaceae, and the precise intergeneric relationships still require further study.