Classification of Rhodopseudomonas palustris: According to "Berger's Handbook of Bacterial Identification" (8th edition, 1974), photosynthetic bacteria that do not produce oxygen are classified as Bacteria, Eubacteria, Rhodospirillum Head (Rhodospirillales). The order Rhodospirillales is divided into suborders Rhodospirillineae and Chlorobiineae. The suborder Rhodospirillaceae is divided into Rhodospirillaceae and Chlorobiaceae, and the suborder Chlorobacteria is divided into Chlorobiaceae and Chloroflexaceae, with 18 genera and about 45 species. Rhodopseudomonas palustris belongs to the family Rhodospirillaceae and the genus Rhodopseudomonas.