Polarised light micrograph of a Euglena organism. Euglena is a genus of of more than 1,000 single celled flagellated microorganisms which possess the characteristic features of plants and animals. They contain a distinct structure called a stigma, or eye spot, which is a small red pigment spot that allows them to detect and move toward light sources, a behaviour known as phototaxis. They can obtain energy through both photosynthesis (using chloroplasts) and by ingesting other organisms. Magnification: 186x when printed 10 centimetres wide.