Fucus spiralis is typically form in a zone high on rocky shores, below Pelvetia but above the other large brown seaweeds (e.g. Ascophyllum nodosum, Fucus vesiculosus) that characterise the mid-shore.Well grown plants are recognisable by the flattened, twisted, cartilaginous and dichotomously branched thallus, lacking bladders, and the large, oval receptacles at the frond tips, each receptacle being surrounded by a narrow rim of vegetative frond.