Spirogyra is a genus of filamentous charophyte
green algae
of the order Zygnematales, named for the helical or spiral arrangement of the chloroplasts
that is diagnostic of the genus. It is commonly found in freshwater
areas, and there are more than 400 species of Spirogyra in the world. Spirogyra
measures approximately 10 to 100μm in width and may stretch
centimeters long.