Triglochin microtuberosum
Tubers 4–13 mm long, globose, clustered closely beneath the rhizomes on short roots. Dorsal surface of mature carpels flat, never keeled. Leaf sheath gradually inrolled touching or overlapping on margins. Leaf erect, thickening and spongy towards base. Terminal raceme 15–24 mm wide, fruit touching, 7–9 per cm of rhachis; fruit base star-shaped. Robust perennial with creeping rhizome. Still or slow flowing water. Fl. spring–autumn