46 



PRINCIPLES OF PLANT CULTURE 



ruptured cambium cells. In plants having more than 

 one cotyledon, the cambium line is usually readily dis- 

 cerned in cross-sections of the stem though it is rather 

 more distinct and the bark is more readily separable in 

 woody than in herbaceous stems. In the latter, the 



C - 



'-7T -V 



FIG. 22. Transverse section of corner of a bean stem (Vicia Fabd). 

 C cambium layer ; e epidermis ; Cu cuticle ; St stoma. The dark, 

 oval-shaped spots extending both sides of the cambium layer are 

 the vascular bundles ; W wood cells of the vascular bundles. Moder- 

 ately magnified. 



part within the cambium line corresponds to the wood of 

 woody stems, and that outside of it corresponds to the 

 bark. Herbaceous stems are those that do not have the 

 hard, firm texture of wood, as the potato, rhubarb and 

 the like. 



69. Uniting of the cambium. Portions of cambium 

 from different plants may unite by growth. If a section 



