154 



THE ANATOMY OF WOODY PLANTS 



FIG. no a 



The truth of this statement can be made apparent by reference to 

 the oak and the birch which represent, respectively, in the species 



found in the 

 Northern United 

 States and Canada 

 the complete ex- 

 emplification of 

 the compound and 

 diffuse types of 

 rays. In Fig. noa 

 and Fig. nob are 

 shown tangential 

 views of the wood 

 of the stem and the 

 root of Quercus 

 rubra, the red oak. 

 In each appear 

 large rays. Above 

 is the illustra- 

 tion of the con- 

 dition in the 

 stem, and here 

 the ray is obvi- 

 ously of the type 

 described in an 

 earlier chapter 

 as compound . 

 Below, the con- 

 dition typical for 

 the root is indi- 

 cated, and it is 

 here equally clear 

 that the large ray 

 is made up of a con- 

 FIG. 110 b S eries of smaller 



FIG. no a and b. Tangential sections of large rays in ra ^ S separated 

 stem and root of Quercus rubra. Explanation in the text. from One another 



