Blue-green algae are a general term for members of the Myxophyceae (Cyanophyceae) family.
The term "blue-green algae" derives from the presence of the predominant pigment c-phycocyanin, a blue-green pigment.
In biological classification, the order is a taxonomic rank that is used to classify species and is denoted by nomenclature codes.
Life, domain, kingdom, phylum, class, order, family, genus, and species are the well-known ranks in decreasing order, with order coming between class and family.
The Myxophyceae family contains 1500 species and 150 genera.
The Myxophyceae class consists of five orders:
Chroococcales: Chroococcales are endospore and cell-dividing unicellular or colonial cyanobacteria, e.g.Chroococcus.
Chamaesiphonales: The phylum Chamaesiphonales is made up of lithophytes that are either colonial or unicellular epiphytes or spore-producing lithophytes, e.g.Chamaesiphon.
Pleurocapsales: An endospore multiplier that includes heterotrichous and filamentous varieties without heterocysts, e.g.Pleurocapsa.
Nostocales: Nostocales are made up of filamentous non-heterotrichous types with heterocysts that reproduce via akinetes and hormogonia or by producing cysts,e.g. Nostoc and Anabaena.
Stigonematales: In contrast to trichomes, which have numerous rows of cells connected by pits, stigonematales feature heterotrichous filaments with genuine branches,e.g. westiella.