PLATE XX. 



Fig. 16S. 



Thready-bark Oak (Casuarina). 



U.idial section showing the penetration 



of the Rays into the Bark. 



Fig. 169. 



Bark of Thready-bark Oak seen from 



without. The oval bodies are the ends 



of the Rays. 



Fig. 170. 

 Bird's-eye Maple. 



Radial section through the worm-eaten 



Bark, showing the origin of the figure. 



(Compnre Fig. 34.) 



Flf. 171. 

 As Fig. 170, but viewed from without. 



