PREFACE vii 



formerly of Santa Barbara, California, who was one of the 

 pioneers in the introduction and cultivation of tropical fruits 

 in California ; and above all, to my present chief, David Fair- 

 child, and my colleagues in the Office of Foreign Seed and 

 Plant Introduction of the Bureau of Plant Industry. To Dr. 

 Fairchild America is indebted for many choice varieties of 

 the mango, the date, and other tropical fruits which are now 

 cultivated in the United States, and for his assistance and 

 encouragement in my own investigations I owe him a debt of 

 gratitude which I can never pay. 



W. J. Krome of Homestead, Florida, has criticized the 

 chapters on the avocado and mango, and added many notes 

 of interest and value to the former. W. E. Safford of the 

 Bureau, of Plant Industry has revised the chapter on the an- 

 nonaceous fruits, and Henry Pittier of the same Bureau that 

 on the sapotaceous fruits. To my brother, Paul Popenoe, 

 I am indebted for most of the chapter on the date. H. H. 

 Hume of Florida has criticized the chapter on the kaki. J. N. 

 Rose of the United States National Museum has furnished most 

 of the data on the tuna and pitaya. Sidney F. Blake of the 

 Bureau of Plant Industry has been of much assistance on 

 matters of botanical nomenclature. J. Smeaton Chase of 

 Palm Springs, California, has rendered valuable aid in the 

 preparation of the manuscript. To all of these men I express 

 my sincere appreciation of their help. 



The line drawings with which this work is illustrated have 

 been made by Mrs. R. E. Gamble of the Bureau of Plant In- 

 dustry. Nearly all of them, as well as most of the half-tone 

 plates, are from my own photographs ; a few are from photo- 

 graphs by P. H. Dorsett of the Bureau of Plant Industry. 



WILSON POPENOE 



WASHINGTON, D. C., 



October 1, 1919. 



