1. Periderm

2. Periderm Phellogen – cork cambium Phellem – cork
Phelloderm – parenchyma like tissue

3. Periderm, Cork, and Bark
Bark = all the tissues outside of the vascular cambium
Inner Bark includes all the tissues from the secondary phloem outward to the phelloderm (or phellogen)
Outer Bark includes the periderm and all the tissue outside of it
Rhytidome
all the successive periderms that develop
bark external to the last formed periderm

4. Periderm developing on a branch

5. Development of Periderm

6. Periclinal divisions of sub-epidermal cells leads to the development of phellogen

7. In Quercus alba, the phellogen originates in sub-epidermal cells
Phellogen has produced 4 layers of phellem (cork) and one layer of phelloderm

8. In Solanum (nightshade), the phellogen arises from the epidermis

9. Phellogen in Clematis originates deep in stem tissue from phloem parenchyma cells below the fiber caps
Phellogen (cork cambium)
Vascular cambium

10. In grape vines, the phellogen also originates in the primary phloem

11. Periderm with tannins Clusia Oak
Tannins deter insects and other animals from feeding on bark, adding to the protective capacity of bark.

12. Tilia periderm

13. Lenticels

14. Lenticels in moonseed form prior to periderm formation
Cuticle

15. Lenticel in Aristolochia

16. Sambucus lenticel

17. Lenticel in ivy stem

18. Rhytidome

19. Robinia rhytidome

21. Pine
Walnut
Paper birch
Crepe myrtle
Sweetgum
White ash
Tilia
White Oak

22. Commercial cork is obtained from Quercus suber, the cork oak tree

24. Harvesting and Regrowth