CYANOBACTERIA (Topical Term)
Wikipedia 1/06 http://en.wikipedia.org/wiki/Cyanobacteria
The autotrophic cyanobacteria were once classified as "blue green algae" because of their superficial resemblance to eukaryotic green algae. Although both groups are photosynthetic, they are only distantly related. They are often referred to as blue-green algae, even though it is now known that they are not directly related to any of the other algal groups, which are all eukaryotes.