I 



866 



A TEXTBOOK OF THEORETICAL BOTANY 



Vascular bundle 



Ground 

 parenchyma 



Fig. 852. — Zea mais. Monocotyledon. Transverse section of 

 the stem showing scattered vascular bundles. 



Epidermis 

 Phellem 



Phellogen st>4n 



m^. 







h^* ,1^^^ 





Phloem 



Primary xylem ^si—^Cr^-^ 

 Tannin pith cells I .(' 



Fig. 853. — Sambiicus nigra. Transverse section of the 

 stem in an early stage of secondary thickening show- 

 ing the phellogen and phellem. 



