The parts of dicot stem that can show dedifferentiation to form secondary meristems.
I.   Pericycle    
II.  General cortex    
III. Medullary rays    
IV. Medulla

In a dicot stem, the medullar ray cells present between the fascicular cambia of adjacent vascular bundles can form interfascicular cambium by dedifferentiation. It later fuses with fascicular cambium and gives rise secondary xylem and secondary phloem. General cortex cells also regain meristematic activity and form phellogen that eventually forms secondary protective tissues called periderm.