ANCIENT PLANTS 



Sclerenchyma. Thick - walled cells 

 among parenchyma for strength- 

 ening, fig. 28. Compare fig. 

 34,*. 



Fig. 28 



Fig. 29 



Cork. Layers of cells replacing the 

 epidermis in old stems. Outer 

 cells, 0, crushed; /', closely 

 packed cork cells; stone cells, 

 s, fig. 29. Compare fig. 95, k. 



Cork cambium. Narrow, actively 

 dividing cells, c in fig. 29, giving 

 rise to new cork cells in con- 

 secutive rows. 



Tracheides. Specially thickened 

 cells in the parenchyma, 

 usually for water storage, /, 

 fig. 30. Compare fig. 95, /. 



Fig. 30 



