There are relatively few obligate submersed aquatic plants (species that cannot tolerate emersion for even relatively short periods), but some examples include members of Hydrocharitaceae and Cabombaceae, Ceratophyllum, and Aldrovanda, and most macroalgae (e.g.
The passage states there are few obligate submerged aquatic plants, but some notable examples include species from the Hydrocharitaceae and Cabombaceae families, Ceratophyllum, and Aldrovanda, as well as many types of macroalgae.