Each thread is a long tube, branching sometimes, but not divided into cells as in spirogyra or Cladophora.
The number of these bands varies much in different species of spirogyra, but is commonly two or three.
Lindsay describes experiments carried on in a reservoir infested with spirogyra.
Any of a genus of filamentous freshwater green algae having cylindrically shaped cells with spiral-shaped bands of chloroplasts. Species of Spirogyra reproduce asexually by cell division and fragmentation and sexually by conjugation. They form green scum on ponds, floated by the oxygen produced by photosynthesis.