Anoxygenic photosynthesis is characteristic of:

Explanation

In Rhodospirillum, the electron donor is an organic compound instead of water hence no oxygen is released, i.e., anoxygenic photosynthesis occurs. In other plants, water is used as an electron donor and H+In summary, Rhodospirillum is the organism characteristic of anoxygenic photosynthesis, while Spirogyra, Chlamydomonas, and Ulva are examples of organisms that engage in oxygenic photosynthesis and produce oxygen during the process.