Figs. 16 and 17. Transverse sections of peach bark examined with ultraviolet epifluorescence illumination ( bar = 10 microns) . In Figs. 16 and 17, the wound surface is approximately 800 microns above the noted cellular changes. Note the presence of phloem fibers (F) in Fig. 16.  Fig. 16 shows tissue 12 days postwounding showing a completely differentiated necrophylactic periderm with phelloderm (PD) and two to four layers of phellem cells (NP). Fig. 17 shows tissues 14 days postwounding, showing a completely differentiated necrophylactic periderm with three to five phellem cell layers (NP) and newly differentiated phelloderm (PD).