Some filamentous species can differentiate into several different cell types:

Timing and trends in cell diameter, loss of filamentous forms and habitat preference within cyanobacteria
Taxa are not drawn to scale – those with smaller cell diameters are at the bottom and larger at the top

Most taxa included in the phylum or division Cyanobacteria have not yet been validly published under The International Code of Nomenclature of Prokaryotes (ICNP) except:

Cyanobacteria cultured in specific media: Cyanobacteria can be helpful in agriculture as they have the ability to fix atmospheric nitrogen in soil.