The rock sea-lavenders comprise a group of closely related, beautiful (1) and delicate (2) plants that have cushions of leaves close to the ground, from which arise branched flowering stems that may be delicate or robust, short or tall, but in all cases support numerous spikes of attractive bluish-lilac coloured flowers (1)(2). In high summer, when flowering en masse, these plants can give a striking purplish 'haze' to the places in which they grow. Almost all of the species that occur in Britain and Ireland are endemics; they are found no-where else in the world (1).