Ectocarpus siliculosus
(Dillwyn) Lyngbye, 1819

Thallus hairlike, forming bushy or entangled masses of filaments, light brown. Filaments uniseriate, branching alternate. Plurilocular sporangia subulate or fusiform, often terminating in a hair. chloroplast band-shaped. Occures on stones and other algae, in littoral and sublittoral down to 10m depth. Rare, widely distributed, multizonal species.