BULLETIN 



<>i 1111: 



UNITED STATES GEOLOGU Ai. AM> GEOGRAPHIl \L SURVEY 

 OF THE TERRITORIES. 



Volume \ 1. I 380. Numbeb i. 



Art. I.— The Vegetation of the Rocky Mountain Re- 

 gion and a Comparison with tliat of other Parti 



of the World. 



By Asa Gray and Joseph D. Hooker. 



I. 



Jin: VEGETATION OF THE ROCK! MOUNTAIN REGION. 



The vegetation of the wide central tract which lies between the At- 

 lantic United States and those which border on the Pacific is replete 

 with interest and importance, both scientific and economical. We are 

 to Bketch its general features, as made known to as by personal obser- 

 vation, by the published observations of others, and by the botanical 

 studies to which we have been devoted. For doing this to much pur- 

 . it is Decessary to compare or to contrast the vegetation of the dis- 

 trict in question with that of the more fertile regions on both sides, and 

 with a somewhat similar wide interior district in another part of the 

 northern temperate zone. 



"the Atlantic States," as contradistinguished from those of the 

 fie, we here mean not only those which touch upon the Atlantic 

 i. but also those which border the Mississippi River, on its w« 



stern Bide; the greal woodless plains being taken as 



their western limit. The term "Rocky Mountain Region," lieiv used in 



and in the lack of a better appellation, we propoc 

 apply in general in such wise as to include the gradually elevated pla- 



which flanks the base of the I fountains on the 



hand, and the equally elevated district or thickly travi 



lain ranges, which extend- westward to the eastern >f the 



revada of California, and I ide Mountains further no 



Rocky Mountains I uvenienl and 



oral, from our point of vi( nderthi uioii 



all t the Wahsatch in< 



We understand the term ( sao* 



1 i 



