Spirogyra is at large genus consisting of about 300 species and is cosmopolitan in distribution. They are found in fresh water such as pools, ponds, lakes, ditches etc and also in slow running water of rivers and streams. They occur as free floating bright green masses in the water but few species such as spirogyra dubia, spirogyra affinis, spirogyra rhijoides develop specialized structure ‘hapteron’ with the help of which they can get attached with substratum. They are slippery in nature so are commonly known as Pond Silk or Water silk.
Vegetative structure: