Bulletin No. 21. S. p. i. Ko. i. 



U. S. DEPARTMENT OF AGRICULTURE. 



DIVISION OF FORESTRY. 



SYSTEMATIC PLANT INTRODUCTION 



ITS PURPOSES AND METHODS. 



BY 



DAVID G. I^AIRCMIIvD, 



Special Agent in Charge of Seed and Plant Introdttction^ 



PREPARED UNDER THE DIRECTION OF B. E. FERNO^Y, 

 CHIEF OF THE DIVISION OF FORESTRY. 



WASHINGTON: 



GOVERNMENT PRINTING OFFICE. 



1 8 Q 8. 



