PLATE LXIII. 



Fig. 43. Cross section of stem of Q. schneckii, in the fourth year, show- 

 ing tracheal tubes, medullary rays, and bark. Bast stippled. X 25. 



Fig. 44. Cross section of stem of Q. macrocarpa, showing the same 

 elements. X 25. 



Fig. 45. Cross section of stem of Q. coccinea, showing the same ele- 

 ments. X 25. 



Fig. 46. Cross section of stem of Q. rubra, showing the same ele- 

 ments. X 25. 



