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Diagnostic features

Unbranched cyanobacterial filaments of blue-green cylindrical cells in a thin sheath. Cells are often at least as long as they are wide.  Cells at the end of the filament are not tapered/pointed, and lack a calyptra (thickened cap; cf. Phormidium). Filaments break easily. Heterocytes absent.  Organelles are absent from the cells, but granules are common.

Typical habitats

Records tend to be from clean water sites.


Kingdom Bacteria
Phylum Cyanobacteria
Class Cyanophyceae
Order Oscillatoriales
Family Phormidiaceae
Common name Cyanobacteria