Sea wormwood

Seriphidium maritimum, sea wormwood, is an aromatic perennial subshrub of the family Asteraceae, native to the coasts of Europe, North Africa and western Asia where it colonises the upper levels of salt marshes, sea walls and brackish shingle. It forms a woody-based, much-branched, greyish plant 20 to 50 centimetres tall, densely covered in fine white woolly hairs that give the whole plant a silvery-felted appearance and a strong sweetish, slightly camphoraceous scent. The alternate leaves are small and twice or thrice pinnately divided into narrow blunt lobes, the upper leaves becoming simpler. From late summer into autumn the stems carry many small, ovoid, nodding flower heads in slender leafy panicles; each head contains only a few yellowish to reddish tubular florets enclosed by woolly overlapping bracts. The fruit is a tiny smooth achene without a pappus. The immature flower heads and leaves contain the sesquiterpene lactone santonin.