UNITED STATES DEPARTMENT OF AGRICULTURE 
DEPARTMENT BULLETIN No. 1422 
Washington, D. C. T October, 1926 
THE HEVEA RUBBER TREE IN THE AMAZON VALLEY 
CARL D. LA RUE, Specialist in Rubber Investigations, Office of Cotton, Rubber, and 
Other Tropical Plants, Bureau of Plant Industry 
CONTENTS 
Page 
Introduction 1 
Purpose of the Expedition 3 
Personnel of the Expedition 4 
Itinerary f 4 
The Genus Hevea S 
Geographical Distribution 7 
Rubber-Bearing Species 8 
Status of the Rubber Industry in the Amazon Valley 9 
Rubber Reserves of the Amazon Valley 36 
Plantation Possibilities in the Amazon Valley 36 
Types of Hevea Brasiliensis in the Amazon Valley 46 
The Disease Situation 56 
Other Trees Which Bear Rubber or Similar Substances . 57 
Need of Introduction of Other Species of Hevea 65 
Summary and Conclusions 66 
Literature Cited 67 
WASHINGTON 
GOVERNMENT PRINTING OFFICE 
1926 
BBHKBnul 
