Preface vii 



sent free (if not out of print) on application to the 

 Directors of the various Stations. 



The Experiment Stations for the southernmost states 

 are at the following places: Texas, College Station; 

 Louisiana, Baton Rouge ; Mississippi, Agricultural 

 College ; Alabama, Auburn ; Florida, Gainesville ; 

 Georgia, Experiment ; South Carolina, Clemson College. 

 The Experiment Stations at Mayaguez, Porto Rico, 

 Santiago de las Vegas, Cuba, and Honolulu, Hawaii, 

 have published bulletins of special interest. 



I am indebted to the Florida Experiment Station for 

 most of the illustrations used in this book. Photo- 

 graphs for Plates IX, XV, and XVI were furnished by 

 Dr. D. G. Fairchild, of the Office of Seed and Plant 

 Introduction, at Washington, D. C. 



P. H. ROLFS. 



GAINESVILLE, FLA., 

 January 1, 1916. 



