CONTENTS. 



Page. 



Introduction 7 



PART I. 



Relations of the Biological Survey to practical agriculture 9 



Need of diversification of crops -. 9 



Sea Island and Egyptian cotton for new sections . 11 



Profitable crops for different climates .. 11 



What the farmer needs to know 13 



Mapping agi'iciiltural regions 13 



Development of agriculture in California 14 



The arid regions .. 15 



Special value of narrow extensions of faunas 15 



PART II. 



Life zones of the United States: Boundaries, native species, and 



important crops 18 



1. The Arctic-Alpine zone 18 



3. The Hudsonian zone 19 



3. The Canadian zone 19 



4. The Transition zone . 80 



(a) The Alleghanian faunal ai-ea 30 



Crops of the Alleghanian faunal area 81 



(b) The arid Transition faunal area ... 35 



Crops of the arid Transition faunal area 35 



(c) The Pacific coast Transition faunal area 37 



Crops of the Pacific coast Transition faunal area 39 



5. The Upper Austral zone ... 30 



(a) The Carolinian faunal area 30 



Crops of the Carolinian faunal area 31 



(6) The Upper Sonoran faunal area 36 



Crops of the Upper Sonoran faunal area 37 



6. The Lower Austral zone . . 41 



(a) The Lower Sonoran faunal area. 41 



Crops of the Lower Sonoran faunal area 43 



(i») The Austroriparian faunal area 45 



Crops of the Austroriparian faunal area 46 



(c) Semitropical or Gulf strip. 49 



Crops of the Semitropical or Gulf strip 49 



7. The Tropical region __. 51 



Crops of the Tropical region 53 



Crops of Tropical Florida . _ 58 



5 



