18 BULLETIN UNITED STATES GEOLOGICAL SURVEY. I Vol.Yl. 



upward over ground which might well nourish the same kind of tree 

 growth. This is the vegetation of the mountains, as distinguished from 

 that <>f tin' high plains. 



Tin- peculiar shrubs of the Rocky Mountains (including the Wahsatch 

 Range and corresponding ranges farther north) arc only Jamesia Ameri- 

 cana, a Bydrangeous genus of no near affinity to any other, except 

 Fendtera, which (equally unique) belongs to a lower region in New 

 Mexico mikI Western Texas, Bobinia Neo-Mexicana, which is an out- 

 lying species on the southeastern border, Quercus tmdulata, Bubus 

 .>sus, Philadelphia microphyUus, Ccanothus Fendleri, and. Berberis 

 U /•/. the latter a species of the Vulgaris type. They are all south- 

 ern : the Northern Rocky Mountains have no characteristic shrub, as 

 they have do characteristic tree. The principal shrubs which they share 

 with the Pacific forest region are Acer glabrum, Prunus demissa, Bubus 

 Nutkanus, Spircea discolor, Ribes, 3 or 4 species, Symphoricarpus oreophilus 

 and rotundifoliu8) Ledum glandulosum, Salix Geyeriana, and, if we come 

 down to such low frutesceDt growth, Pachystima Myrsinites, and Berberis 



)•<)>< IIS. 



Arctostaphylos pungens, a species of the Mexican plateau, which appears 

 to have taken a wonderful development and diversification in California, 

 of which it is the prevalent shrub, has reached the western portion of 

 the Rocky Mountain Region as high in latitude as the forty-first parallel, 

 and at an altitude which brings it among the forest shrubbery. 



The shrubs which are common to this and to the Atlantic forests are 

 not numerous nor of sufficient, interest to be specified. They are such 

 as Ampelojisis, Cornus stoloni/era, and the like. The genus Shepherdia. 

 however, is somewhat noteworthy. S. argentea, the Buffalo Berry, which 

 seems most at home in the Northeastern Rocky Mountains, and which 

 extends much beyond them in the same direction, along with its rela- 

 tive FJaiignus argentea, extends southward even to New Mexico, and 

 westward to the Sierra forming that rim of the Great Basin; and it is 

 accompanied by 8, Canadensis, a characteristic shrub of the northern 

 border of the Atlantic forest. The third species of*the genus is peculiar 

 to Southern Nevada. 

 Of the shrubs which traverse the continent and completely enter the 



Pacific forest the following are the principal: 



Rhus glabra. Betula glandulosa. 



Ulius aromatica, Alnus incanat 



Xrillia opulifolia. Corylus rostrata. 



I'ii r us sa in Inn [folia. JumperUB communis. 



dymphorioarpui mux mosus. Jwiiperus sdbina ? 



8ymphorioarpui ocoidentalis. Ardostaphylos 1'ra-f'isi. it we con- 



Lonioera involucrata. (\v>vk'\h\ to one so low, 



i mo$u$ ( pnhms). 

 The Last three and the Sambuout arc of the Old World. North Asiatic 



as well M European. They are all of northern range, and are there 



