Oscillatoria is found in rain water of pools, ponds, rivers, streams, lakes and in polluted water. Some of the species of Oscillatoria are plank tonic, some are found in hot water springs e.g O. terebriformis, and some species of Oscillatoria are found in saline waters. e.g. O. limosa. Oscillatoria in unbranched and filamentous. The trichome consists of cells which are arranged in uniseriate fashion. Oscillatoria species show Gaidukov phenomenon. Species of Oscillatoria can assume different shades when they are provided with light of different wavelengths. The trichome shows gliding movement as well as oscilllatory movement. During vegetative growth of the trichome, some cells of the trichome are filled with mucilage and become dead. These cells are called necridia. Thus Oscillatoria reproduces by the formation of Hormogonia and by fragmentation.