64 THE VEGETATIVE FUNCTIONS OF PLANTS 



FIG. 48. 



FIG. 49. 



FIG. 48. White lupine (Lupinus albus). Made 

 semi-transparent by being placed for several hours 

 in a weak aqueous solution of potassium hydroxide. 

 After this treatment the nbro-vascular system may 

 be clearly seen (through the surrounding tissues) 

 by transmitted light, cot, cotyledons; h, hypocotyl; 

 r, main root; br, br 1 , branch roots of different ages. 

 Note the endogenous origin of the branch roots. 



FIG. 49. The system of leaf-veins in a leaf of the 

 common rubber-plant (Ficus elastica) . The veins are 

 connected with the root by means of the vascular 

 bundles extending through the stem and roots. 



