Sphacelaria cirrosa (Roth) C.Agardh
Thallus filiform, forming olive brown, stiff, feather-like tufts, to 50 mm long. Filaments segemented, each segment with (1-) 4-10 (-24) longitudinal walls, but very rarely with secondary transverse walls. Branches numerous, in one plane; apical cells large and conspicuous. Attached by a minute basal disc; rhizoids sparse or absent. Propagules common, stalk of the propagule narrows to the base, often with an apical hair and usually 3 cigar-shaped arms. Unilocular sporangia pedicellate; plurilocular sporangia oval, rare, pedicellate.