PLATE LIV 
Cross section of cow oak, a white oak, showing normal and abnormal tyloses. From 
top to bottom are bark (B) and three annual growth rings (Ri, i?2, #3). 
Fig. 1.—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 ). 
