The history of seaweed systematics in South Africa may be divided into three phases. From the 18th century until 1930 collections were made primarily by visiting plant collectors, and were studied by European phycologists. The initiation of detailed ecological studies on rocky shores from 1932 necessitated the naming of species. G.F. Papenfuss, a South African who was trained in the U.S.A. and Sweden, was a major catalyst, supervising many students who included South African algae in their research. Pocock, Simons and Seagrief were prominent locally in documenting the flora in this period. Since 1980 there has been a major revival with, among others, Richard Norris from the USA producing a large body of work on Natal seaweeds, and Herre Stegenga from the Netherlands collaborating with local phycologists to produce a detailed flora of west coast seaweeds. More than 800 species of red, green and brown seaweeds have been recorded, making up one of the richest marine floras in the world, with a high level of endemism. Priorities for further work include detailed investigations on the south coast and the overlap with tropical East Africa, the green algae of the south and east coasts, as well as detailed phylogenetic studies on many groups.