Beach grass is clearly one of the most critically important dune plants. Its fast growing rhizomes can respond to the constantly shifting sands, enabling this species to serve as a significant sand binder, Sand reed grass (Calamovilfa longifolia) is also a common grass of the dunes, bearing tough rhizomes that allow it to perform a similar ecological role. The latter species, which is usually a much taller plant than beach grass, can also be distinguished by its more open seed heads.