Phormidium willeiPhormidium willei is a species of bacteria that is able to photosynthesize to make food, similarly to plants.AnatomyBacteria of the genus Phormidium occur in rows of cells of similar size. They form filaments called trichomes. Many trichomes are enveloped in a firm casing, but in this genus the casing is almost non-existent. This gives the filaments easier mobility in all directions.Nitrogen fixing abilityThis species of Phormidium is able to fix nitrogen, but unlike other bacteria, it is uncertain whether or not it has cells specialized for that particular purpose.HormogoniaFragments of filaments of Phormidium willei are called hormogonia. They consist of dozens of cells, which sometimes break off to reproduce by establishing new colonies.Danger to HumansLike other species of cyanobacteria, this species can cause skin irritation in humans who come in close contact with them in the tropics.