MYRTLE FLAG. SWEET FLAG. Northern temperate regions. The rhizomes are used by confectioners as a candy, by perfumers in the preparation of aromatic vinegar, by rectifiers to improve the flavor of gin and to give a peculiar taste to certain varieties of beer. In Europe and America, the rhizomes are sometimes cut into slices and candied or otherwise made into a sweetmeat. These rhizomes are to be seen for sale on the street corners of Boston and are frequently chewed to sweeten the breath. In France it is in cultivation as an ornamental water plant.