Spirogyra

Spirogyra (common names include water silk, mermaid's tresses, and blanket weed) is a genus of filamentous charophytegreen algae of the family , named for the helical or spiral arrangement of the chloroplasts that is characteristic of the genus. Spirogyra species, of which there are more than 500, are commonly found in freshwater habitats. Spirogyra measures approximately 10 to 150 micrometres in width (though not usually more than 60) and may grow to several centimetres in length.