18 BULLETIN UNITED STATES GEOLOGICAL SURVEY. Wol.YJ. 



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

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

 that of the high plains. 



The j)eculiar shrubs of the Eocky Mountains (including the Wahsatch 

 Eange and corresponding ranges farther north) are only Jamesia Ameri- 

 ca7ia, a Hydrangeous genus of no near affinity to any other, except 

 Fendlera^ which (equally unique) belongs to a lower region in ]S"ew 

 Mexico and Western Texas, Bohinia JSfeo-Mexicana^ which is an out- 

 lying species on the southeastern border, Quercus undulata, Buhus 

 deliciostis, Philadelphus onicrophylhis, Ceanothus Fendleri, and Berberu 

 Fendleri, the latter a species of the Vulgaris type. They are all south- 

 ern ; the Northern Eocky Mountains have no characteristic shrub, as 

 they have no characteristic tree. The principal shrubs which they share 

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

 Nutkanus, S^ircea discolor, Bibes, 3 or 4 species, SympJioricarpus oreopJiilus 

 and rotimdifolius, Ledum glandulosum, Salix Geyeriana, and, if we come 

 down to such low frutescent growth, Fachystima Ifyrsinites, and Berber is 

 repens. 



Arctostapliylos 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 Eocky Mountain Eegion 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 Ampelopsis, Cornus stolonifera, and the like. The genus Shepherdia, 

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

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

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

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

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

 accompanied by S. 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 : 

 Bhus glabra. Betula glandulosa. 



BJms aromatica. Alnus incanaf 



IfeilUa opulifolia. Gorylus rostrata. 



Pyrus sambucifolia. Juniperus communis. 



Symphoricarpus racemosus. Juniperus sabina f 



SympJioricarpus occidentalis. ArctostapJiylos Uva- JJrsi, if we con- 



Lonicera involucrata. descend to one so low. 



Sambucus racemosus {pubens). 



The last three and the Sambucus are of the Old World, North Asiatic 

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



