The sea holly, Eryngium maritimum, is a species of Eryngium and is native to most European coastlines. It resembles a plume thistle in that its flower is burr-shaped, but the flowers are a striking metallic blue rather than mauve. When protected from winds this dune plant grows to a height of 20 to 60 cm. Although widespread, it is considered endangered in many areas, such as Germany where it has become locally extinct in several districts. It is drought tolerant and deer-resistant.