The Nostocales are an order of
cyanobacteria
Cyanobacteria (), also known as Cyanophyta, are a phylum of gram-negative bacteria that obtain energy via photosynthesis. The name ''cyanobacteria'' refers to their color (), which similarly forms the basis of cyanobacteria's common name, bl ...
containing most of its species. It includes filamentous forms, both simple or branched, and both those occurring as single strands or multiple strands within a sheath. Some members show a decrease in width from the base, and some have
heterocysts.
References
Bacteria orders
{{cyanobacteria-stub