150 



TIMBER PINES OF THE SOUTHERN UNITED STATES. 



As usual in couifers, the tracbeids are largest in the roots and smallest in the limbs. In these 

 pines, especially in Longleaf Pine, they are larger in well-grown wood than in that of e.^tremely 

 stunted trees, though verj' narrow rings in otherwise normal trees do not share this diminutive size 

 of the tracheid. (See fig. 18, A and B, where a few very narrow rings are made up of elements of 

 normal size.) 





i^XJ 



Tlie f )I1 

 and that of 

 examined: 



Fin. 18.— Cross section of normal and stunted growth in L<.ngleaf Pine. 



owing average figures illustrate the difierence between wood from very stunted trees 

 normal trees in Longleaf Pine, of which we give an average from an extensive series 



