n.
Genus of blue-green algae ( cyanobacteria ).
Found as plankton in shallow water and on moist soil, they occur in both solitary and colonial forms and are capable of nitrogen fixation. In northern latitudes in summer, extensive growth of Anabaena may form water blooms that remain suspended instead of forming a surface scum. A toxic substance produced is fatal to cattle and other animals if present in drinking water in sufficient concentration.