Cellular Organization of Plants and Animals 57 



EPIDERMAL 



Chloroplast 



pi. 



Stoma 



Nucleus 

 Gua^d Cell 



SCLERENCHYA 



Nucleus 



MERISTEMATIC 



CO"RK 



PARENCHYMA 



Spiral. 



Q 



® 4 © ® "® (S ■ ®_"0'(i"'^"'^';i'J i'^'i) 



_ _ _ _ * 





Z'" 



Tracheid 



Tracheal "Tubes 



Sieve Tube 



CONDUCTING 



Sieve Plate 



Fig. 18. — Plant tissues shown somewhat diagrammatically. The sclerenchyma 

 tissue shown is a stone cell (sclereid) type of mechanical tissue. The conducting 

 tissues shown include three types of tracheids (found in xylem), three types of 

 tracheal tubes (found in xylem), and sieve tubes with their adjacent, nucleated 

 companion cells (found in phloem). L, Longitudinal section; X, cross section. 



