Differential interference contrast (DIC) light micrograph of a cyanobacteria Nostoc flagelliforme. Nostoc flagelliforme is a species that can survive under a variety of conditions, such as low rainfall, extreme temperatures, and limited nutrients. Nostoc flagelliforme's colonies are protected by a sheath that helps maintaining a constant environment around the colonies (as seen surrounding the cells in the photograph). Magnification: x425 when printed at 10 centimetres wide at its longest edge.