any of a group of bacteria that reproduce by budding. Each bacterium divides following unequal cell growth; the mother cell is retained, and a new daughter cell is formed. ( binary fission, in which two equal daughter cells are produced from the unilateral growth and division of the mother cell, is typical of most bacteria.) In budding, the cell wall grows from one point on the cell (polar growth), rather than throughout the cell; this permits the development of more complex structures and processes. Most budding bacteria develop cytoplasmic extrusions, such as stalks (Caulobacter), hyphae (Hyphomicrobium), and appendages (Stella). Budding bacteria are most often aquatic and can attach to surfaces by their stalks; others are free-floating.