A reassessment of the phytogeographic characterization of Temperate Pacific South America

In 1980, a study of geographic distribution patterns and geographic affinit ies of benthic algae of temperate Pacific South America (5-55 degreesS) pro vided a first characterization of these coasts. High endemism and limited f loristic exchange with the Tropical Pacific and with islands in the South P acific at various distances from the continent were two outstanding feature s of the marine flora. A partial blockage of species exchange partially acc ounted for a peculiar latitudinal pattern of species richness that increase s with increasing latitudes. In contrast, there was reduced species richnes s in comparison with other climatically equivalent regions that have contac t with more effective routes of migration. Over the last two decades, more than 30 taxonomic and biogeographic studies on this benthic marine flora ha ve been completed, adding a significant number of new records for the area. New studies test the above characterization and indicate that the new data add support to several key aspects of the phytogeographic characterization of this coastline. The relative importance of the various floristic compon ents at different latitudes, the isolated character of this flora and the l atitudinal pattern of increasing species richness to higher latitudes are s hown.