Fucuses are brown seaweed which cover alot of the middle of rockyshores in the UK. Serrated wrack can be told apart, quite easily from the other Fucus species once you know what to look for. Its a very flat fucus, with no bumps or lumps along the fronds, but the main way to tell is at the end of the fronds it has distinctive serrated edge – which looks like its been cut by childrens scissors with a wavy pointy edge!