The members have been further distinguished in to A. Prosthecate bacteria- Budding type- Hyphomicrobium ; non-budding- Caulobater; B. Nonprosthecate bacteria- Planctomyces, non-budding- Gallicnella ; C. Morphologically unusual budding bacteria- involved in iron and manganese deposition- Metallgenium ; and D. Spinate bacteria a is a- This is a heterogenous group with members sharing the common feather of possessing extensions or protrusions from the cell. The appendages called prostheacae may have in some members a reproductive function and in others a physiological purpose. Some members re produce by budding and other by binary fission. Some members use these appendages to efficiently concentrate the available nutrients. The appendages in Caulchacter referred to as stalks provide a holdfast by which the cell can attach to a substratum. The arrangement of appendages provides a characteristic shape such as star-shaped structure.