ACKNOWIEDGIIEHTS. 

 0000 



The author desires to avail himself of this oppor- 

 tunity to tender his thanks to those under whose guidance 

 he has vrorked while a student at the Johns Hopkins Uni- 

 versity, namely to Professors Remsen» Morse, Jones, An- 

 drews, and to Doctors TJ.ngle and Acree for inct ruction 

 in lecture room and laboratory. 



He is especially indebted to Dr. S. F» Acree, at 

 whose suggestion this research work was undertaken, for 

 counsel and assistance in its prosecution. 



He would also thank Messrs. Parke, Davis and Co., 

 of Detroit, Mich,, for the preparation of the crude ma- 

 terial used in this investigation, and the U. S. Depart- 

 ment of Agriculture, Washington, D. C. for electrotypes 

 of figures 17, 18, and 19 in Bulletin Ho. 20, Division 

 of Botany, 



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