Spirogyra is a cosmopolitan, freshwater, filamentous green alga, represented by about 300 species. Most of them are green floating in stagnant ponds and pools, a few species are attached and some occur in running water (S. adnata). It was discovered by Link. Spirogyra is commonly known as pond silk, water silk, pond scum or mermaid’s trees because of their bright green silky appearance.
