Spirogyra

Spirogyra is a genus of filamentous green algae, easily recognized by its long, silky, unbranched threads composed of cylindrical cells joined end-to-end.​

Key Structural Features

Filamentous Form: Spirogyra forms long, slender, unbranched filaments that float as green, slimy masses in freshwater bodies like ponds and ditches.​

Cell Wall: Each cell has a double-layered wall—the inner layer is cellulose (providing rigidity), while the outer pectose layer dissolves in water, producing the slimy mucilage that makes Spirogyra slippery.​

Cytoplasm & Nucleus: The cytoplasm lines the cell wall, and a large central vacuole fills most of the cell’s interior. The nucleus is centrally suspended by thin cytoplasmic strands.​

Chloroplasts: The most distinctive feature is the presence of one to several spiral (helical), ribbon-shaped chloroplasts per cell, giving the genus its name. These chloroplasts contain pyrenoids, which store starch.​

Reproduction: Spirogyra reproduces by vegetative fragmentation and by both scalariform and lateral conjugation (types of sexual reproduction involving the fusion of contents from adjoining filaments or cells).​

Habitat: It is commonly observed in freshwater environments, where it plays a crucial ecological role in oxygen production and as food for aquatic organisms