Ruppia maritima
Peduncle at fruiting stage not coiled or loosely coiled 1–2 times. Flowers submerged. Fruit black, 2–3 mm long, asymmetrical, with stalks c. 1 cm long. Leaves linear, up to 5 cm long, c. 0.5 mm wide, with an acute or obtuse tip. Coast. Estuaries in brackish to very salt water. Fl. spring–autumn