Vol. 48 No. 12 
BULLETIN 
OF THE 
TORREY BOTANICAL CLUB 
DECEMBER, 1921 
Phytogeographical notes on the Rocky Mountain region 
X, Grasslands and other open formations of the 
Montane Zone of the Southern Rockies 
PER AXEL RYDBERG 
In a previous article* I have discussed the wooded formations 
of the Montane Zone. In this article the remaining formations 
are taken up. In these, the plants of the plains and foothills 
make up a larger proportion of the vegetation than in the wooded 
formations. The river valleys, meadows, and hog backs have a 
flora much more like that of similar habitats in the foothill region 
and even on the plains. The transcontinental elements and those 
from the prairie region are much more numerous. 
The formations have been arranged so that the hydrophytic 
are first taken up and then the mesophytic, the most xerophytic 
being left until the last. The species followed by a dagger, ‘7’, 
are confined to the Southern Rockies. 
A. AQUATIC FORMATIONS 
Lakes are not very common in the Montane Zone of the 
Southern Rockies. In the higher parts they are mostly glacial, 
fed by the snow fields, and contain little vegetation. The brooks 
are swift and rarely form lakes or ponds in the higher regions. 
Most of the lakes are found in the lower river valleys and ‘‘ Parks’ 
* Bull. Torrey Club 47: 441-454. 1920 
[The BuLietIN for November (48: secaca was issued January 19, 1922.] 
