Sea kale was first discovered in Sweden by Pehr Kalm, a learner of Carl von Linné. Kalm saw this species at Koster in the northern part of Bohuslän in 1742. Pehr Kalm initially thought it was a farmed type of cabbage that had spread in wild nature, but soon he realized that it was wild growing.

At Kramkistesund in Stångehuvud are several specimens of sea kale.

The leaves of sea kale are large, fleshy and distinctive gray-green, due to a wax layer that protects against excessive evaporation. The root system goes deep to reach water - necessary on a boulder beach, where only coarse soil material remains. When the centimeter-sized, spherical fruits have ripened and dried in the autumn the stalks are broken of waves and wind. They end up in the water, float away and are eventually thrown onto land, where individual seeds at best can give rise to a new plant.

The sea kale is in June covered with white flowers.
In the foreground Vicia cracca.