56 



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, o, crushed; k, closely 

 packed cork cells; stone cells, 

 s, fig. 29. Compare fig. 95, ^ 



Corli 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, t. 



Fig. 30 



