Rydberg: Phytogeographical notes 25 



The forest in the Black Hills consists mostly of bull pine, 

 Finns scopuloriim. On the northern exposure of Harney Peak 

 and the northern end of the limestone district above an altitude 

 of 4,500 feet, there is some spruce, but it is not Picea Engelmannii 

 but a form of the white spruce, Picea canadensis, with unusually 

 short cones. This attains a height of about 100 feet and a diam- 

 eter of nearly three feet. Betiila papyrifera, B. fontinalis, Populus 

 angiistijolia and P. tremidoides are present. In the Foothill Zone 

 are added Qiierctis macrocarpa, Negundo interius, Populus Sargentii, 

 P. acuminata, Ulmus americana, Ostrya virginiana, and Sahina 

 scopuloriim. From this can be seen that the Black Hills do not 

 represent a typical part of the Northern Rockies, as their forest 

 flora contains fully as many species belonging to the eastern United 

 States. 



New York Botanical Garden 



