The growth rate in higher plants is divided into three main stages-lag, log and senescence. When the cell loses its ability to divide, it moves towards differentiation. Differentiation provides structures that are linked to the functionality of the product. The general rules for differentiation are the same for cells, tissues, and related organs. A differentiated cell can then differentiate or re-differentiate. Since differentiation in plants is open, development can be flexible. In other words, development is the combination of growth and differentiation.