Ruppia L. >
Inflorescence always 2-flowered. Carpels 2–19. Mature fruit usually stalked Ruppia
Peduncle at fruiting stage coiled several times. Flowers floating or close to the water surface. Fruit submerged
Leaves obtuse or acute, 5–10 cm long, usually less than 0.5 mm wide. Carpels 4–12 but usually 6–8. Peduncle at fruiting stage usually more than 10 cm long. Fruit slightly asymmetric, 2–3 mm long. Coast. Lakes and lagoons in brackish to very salt water and usually in water less than 1 mdeep. Fl. spring–autumn Ruppia polycarpa