Surely one of the most inhospitable habitats for a plant to survive in is the sand on a beach. There is no firm soil here to put your roots down into to get stability and moisture, just fine, loose granules of fine rock. Despite this the sea rocket (Cakile maratima) manages to grow in these conditions quite successfully and can be found on sandy, not shingle, beaches above the high water line.
Rockets are usually members of the cabbage or crucifereae family having four petals in the shape of a cross. The sea rocket is a member of this family and has the right form of flower but the plant itself is much more fleshy than its cousins and this enables it to store what little moisture it can glean. It is a rather floppy plant with several flowering stems and produces flowers in July and August which can be various shades of lilac from very pale to quite dark.
The seeds have a fiery flavour but it is a strange plant chemically with the seeds in particular containing erucic acid which can induce heart failure in some animals and yet appears to be beneficial to humans as it can be found in rapeseed oil used as a modern replacement for butter and margarine.Sea Rocket: shore fire