SHADE TREES. 



223 



Fio. 95. Showing cross-section of Carolina poplar (1'optilusdeltoide* Marsh). 1, Cross- 

 section of normal stem, enlarged; 2, same, showing abnormal growth; 3, naked-eye 

 view of same; 4, section of a normal stem: 5, cross-section of trunk of tree showing 

 the splitting of the bark; a, bark; 6, cork cambium; c, cortex; d t phloem; e, abnor- 

 mal parenchyma ; /, cambium ; g, wood or xylem. 



