COLORADO WILD FLOWERS 



II 



altitude there is a loweiing of temperature to the extent of about three 

 degrees Fahrenheit so that if the people in Denver are fanning them- 

 selves and trying to keep cool in a temperature of eighty in the shade, the 

 camper or fisherman up at Tolland will find it cool and pleasant for 

 strenuous exercise, since he is 4,000 feet higher and is enjoying a tempera- 



Fig. 11. — Mesas near Boulder, Colo. 

 The mesas are flat-topped hills which extend out, peninsula-like, to the plains. Next 

 to the mountains the mesas are covered with pines while toward the plains they are as 

 treeless as the plains themselves. 



ture' of sixty-eight. This difference of temperature has its effect on the 

 plant population. Indeed there are very few wild plants at Denver 

 which also grow wild at such an altitude as that of Tolland. 



Differences observed in regard to plants of the mountains which 

 distinguish them from the plains species are generally ascribed to "alti- 



