Green algae and sphagnum moss. Polarised light micrograph of colonies of Desmidium swartzii desmids (small cells, vertical) and Spirogyra sp. green algae (long cells, right) amongst Sphagnum sp. moss leaves (background). Desmids are a common group of freshwater single-celled algae that have intricate cell walls. Spirogyra is a filamentous green algae named for the spiral arrangement of its chloroplasts. It's cylindrical cells connect end to end in long green filaments. Magnification: x200 when printed 10 centimetres wide.