Polarised light micrograph of Coleochaete sp. algae and diatoms on a watermilfoil (Myriophyllum verticillatum) leaf. Coleochaete algae is filamentous, in which a number of filaments radiate from a central point. They form flat, sprawling discs on solid surfaces in freshwater streams. Diatoms are a type of algae that form a significant portion of the Earths biomass. They generating about 20 to 50 percent of the oxygen produced on the planet each year. Magnification: 186x when printed 10 centimetres wide.