1 Eelgrass – a short description
All species within the genus Zostera are submerged, hydrophytic plants, growing in salty to brackish water. Only two species are endemic in the Netherlands: (common) eelgrass (Zostera marina) and dwarf eelgrass (Zostera noltii).
Even though not closely related to true grasses (Poaceae), eelgrass has some more or less similar morphological features, hence the name. Common eelgrass has leaves of about one metre long and roughly half a centimetre wide (Fig. 1). The leaves are connected to stems growing from a perennial rhizome. Like grass the species can easily propagate through its rhizome, forming extensive mats. Dwarf eelgrass is of similar shape, but smaller in every aspect (Fig. 2). The two species prefer a slightly different ecotope: common eelgrass appears in a zone between just above and up to several meters below low-water mark, while dwarf eelgrass grows in the zone between low and high- water mark (Hegi 1981, 203-213).