The anabaena is characterized by the presence of unbranched trichomes which possess intercalary heterocysts. They are specialized for the process of nitrogen fixation.
- Cyanobacteria are unicellular, colonial or filamentous.
- They are found in marine and terrestrial habitats.
- The colonies are surrounded by gelatinous sheath.
- They often form blooms in polluted water bodies and results in eutrophication.
- Some of these organisms fix atmospheric nitrogen in specialized cells called heterocysts, Examples: Nostoc and Anabaena.
