Isoetaceae . . . . . Quillwort
Isoetes . . . . . Quillwort
Isoetes lacustris . . . Quillwort
Locally frequent in N & W Br usually submerged near the edges of lakes
Other spp. include the less common Spring Quillwort (I. echinospora) - found mostly in W Ire and W Br, and the rare Land Quillwort (I. histrix) which is only seasonally submerged in CI and W Cornwall.
See also:
Lobelia dortmanna
Littorella
Subularia
Juncus