Guide to the seaweeds of Britain and Ireland.

British and Irish shallow seas contain an astonishing 7% of the world’s seaweed species, around 700 different seaweeds, and yet most divers, snorkellers and rockpoolers can put names to only a handful of them. This guide aims to de-mystify seaweed identification for the non-specialist. It includes over 200 seaweeds, all of which can be identified in the field.