planktothrix agardhii planktothrix agardhii planktothrix agardhii is a species of cyanobacteria belonging to the family oscillatoriaceae. planktothrix agardhii scientific classification domain: bacteria phylum: cyanobacteria class: cyanophyceae order: oscillatoriales family: microcoleaceae genus: planktothrix species: p. agardhii binomial name planktothrix agardhii(gomont) anag. & komar it has cosmopolitan distribution.