Posidonia (L.) Delila, 1813 is an aquatic plant, endemic to the Mediterranean Sea, belonging to the family Posidoniacee (Angiosperms Monocotyledons).
It has features similar to terrestrial plants, has roots, a rhizomatous stem and leaves up to a meter long ribbon and united in tufts of 6-7. It blooms in autumn and in spring produces floating fruits commonly called “sea olives”.
Shape of the underwater meadows that have considerable ecological importance, constituting the climax community of the Mediterranean Sea and exerting a significant action in the protection of the line of coastline from erosion. Inside live many animal and plant organisms that are the Prairie nourishment and protection.
The posidonieto is considered a good bio-indicator of the quality of coastal marine waters.