3f< 



TUK T'LANT CELL. 



the cork is distinguished as a layer of cells some five or six deep, 

 lying just internal to the epidermis ; one or two lines of these 

 cells may be seen to possess protoplasmic contents, the outer cells 

 being empty and often pressed together (see Figs. 22 and 23). 



Fig. 22.— A Portion or a Longitldinal Section through thi; Vouno 

 Stem of Sainhuciis to show the Cork.— s, Cork-cell- : .t, cork- 

 cambiiim ; jih, phelloderni. 



Fiy. 23. — Oldef. Cork-Cells from the Potato Ti:eer.- 

 cork-eells being cast off. 



-l\ Compound 



The cells containing protoplasm are known collectively as the 

 cork-cambium* or phellogen, and, strictly speaking, should come 



* A similar layer occurs in leaf-petioles at the time of separation of the 

 leaf in the autumn ; it is known as the absciss-layer, and separation takes 

 place along the middle lamellae. 



