Fig. 3. Light micrograph of longitudinal section through tissue undergoing dedifferentiation during generation of new phellogen after mechanical wounding of bark of healthy 2-year-old peach bark. Outside bark in all figures is oriented toward top of plate. Bar = 10 microns. Fig. 3. shows section through the secondary phloem 48 hr postwounding showing mitotic activity associated with tissue redifferentiation. Cells to the left of the arrows participate in phellogen generation; cells to the right are becoming hypertrophied and developing lignified walls and intracellular suberin linings.