Differentiation is the process by which cells derived from meristems (apical, intercalary, and lateral) mature and undergo structural and physiological changes to perform specific functions. During this process, the cells lose their ability to divide and form permanent tissues like parenchyma, xylem, and phloem. Redifferentiation is the process where cells that have already undergone dedifferentiation (i.e., differentiated cells that have regained the ability to divide) once again lose their ability to divide and mature to form new, specialized permanent tissues. For example, the cells of the secondary meristems, like the cork cambium, divide and then redifferentiate to form cork (phellem) on the outer side and secondary cortex (phelloderm) on the inner side.