Algal phytogeography of the European Atlantic coasts

It is concluded on the basis of data gathered from the literature and of our personal observations, that the algal phytogeographic provinces as assumed by several authors do not exist. The algal floras of NW. Spain and Brittany are richest in species. From these two regions down to the south but far more so up to the north the algal flora gradually changes mainly by species dropping out and being only partially replaced by others. One very obvious floristic discontinuity is not correlated with a discontinuity in the temperaturerange of the surface-water, namely the one along the west coasts of the British Isles. The floristic discontinuity Arctic Europe-Spitsbergen is correlated with a temperature discontinuity. Floristically and as regards temperature-range of the surface-water, the Côte Basque finds its logical place in between NW. Spain and Morocco.