- predominantly photosynthetic, i.e. chlorophyll on intracytoplasmic membranes are present and involved in photosynthesis
- blue-green in colour due to the presence of phycobiliproteins.
- occurring singly (unicellular) or in colonies (filamentous, e.g. Anabaena sp.)
- heterocysts capable of nitrogen fixation
- nonmotile or by gliding motility
- reproduce by binary fission
Word origin: Greek (kyanós) = blue + (phyta) = plant.
See also: cyanobacteria