Differential interference contrast (DIC) light micrograph of Synura uvella, a freshwater heterokont alga colony. Synura colonies are formed by variable numbers of cells held together at their posterior ends. Here the colony is slightly squeezed to show more details at a higher magnification. Each cell bears two flagella and is covered with overlapping silica scales. Magnification: x870 at a print width of 10 centimetres.