Triglochin rheophilum Aston

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