Dictionary.net

Certain light, round, depressed, or oblong masses -inodorous and insipid-in which rushes, hairs, and the debris of shells are met with. These are found on the seashores, and have been regarded by Spielmann as consisting chiefly of the roots of the Zostera Marina seu Maritima, Alga Marina, (Big tangles, Ware, Wair, Sea-icare,) Phucagrostis minor. Iodine is detected in the ashes, which accounts for their success in goitre. They have, also, been given as a vermifuge.