The Chroococcales (/ˌkroʊəˌkɒˈkeɪliːz/[2]) are an order of cyanobacteria in some classifications which includes the harmful algal bloom Microcystis aeruginosa.[3] Molecular data indicate that Chroococcales may be polyphyletic, meaning its members may not all belong to the same clade or have the same common ancestor.[1]
The order is characterized by single, floating cells or colonies which are embedded to a matrix. Also, a lack of differentiation between apical and basal structures exists.[4]