Although said to be commonly found around our coasts, I have found it more commonly along the western Atlantic seaboard. It's a pretty wee plant with pink or sometimes white petals and succulent leaves and is a nice winter coastal edible, though can be found at most times of the year. It's got a sort of radishy mustard taste which is to be expected from the crucifers I suppose and is certainly much stronger in taste than the cultivated salad rocket, apparently the root is edible too though I'm reluctant to dig up a plant unnecessarily just to try it.
It has a medicinal property in that a poultice is supposed to help heal infected wounds and cuts.
The flowers are supposed to represent the colour of mermaids tears!