PLATE LIV 



Cross section of cow oak, a white oak, showing normal and abnormal ty loses. From 

 top to bottom are bark (B) and three annual growth rings (Ri, R2, #3). 



Fig. i. Wound tyloses (WT) induced by the felling of the tree and the sudden 

 cessation of sap flow. 



Fig. 2. No tyloses (V); empty vessels. Normal tyloses not yet developed. 

 Fig. 3. Young (YT) and well-developed normal tyloses (T). 



