Light micrograph of the freshwater golden alga Synura petersenii. Synura forms spherical, free-floating colonies of egg-shaped cells, each with two flagella. The cells each have two golden brown plastids and a nucleus. The surface of the cells is mostly covered with siliceous scales. Culture material of the algae collection at the University of Cologne (CCAC). Microscopic contrast method : Differential interference contrast. Magnification 920x at a print width of 10 cm.