Triglochin L. >
Carpels 3 or 6, cohering at the apices only. Fruit a follicle Triglochin
Rhizomes thick, tuberous roots present. Fertile carpels 3–6 not alternating with barren ones. Basal leaf without ligule
Tubers elongated, more than 13 mm long, distributed at a distance from the rhizome on long roots. Dorsal surface of mature carpels keeled or ridged
Leaves submerged, thin, similar on both surfaces, (maybe glossy on stranded specimens), sometimes spiral or margins undulate. Leaf sheath narrow never meeting across the blade, margins tightly inrolled. Terminal raceme 15–30 mm wide, fruit mostly touching, 4–9 per cm of rhachis. Fruit straight or slightly twisted. Robust perennial. Swiftly flowing clear water. Fl. spring–summer Triglochin rheophilum