PAPERS ON BOTANY 



121 



A COMPARISON OF CERTAIN ROCKY MOUNTAIN 



GRASSLANDS WITH THE PRAIRIE 



OF ILLINOIS 



GEORGE D. FULLER, UNIVERSITY OF CHICAGO 



Grasslands occur at varying altitudes in mountain regions 

 and are almost as widely distributed as the peaks and ranges 

 themselves. Alpine and sub-alpine meadows are perhaps best 

 known, but in them the preponderance of other herbaceous 

 and low woody plants over the grasses is such that the fitness 

 of the term grassland may well be questioned. At somewhat 

 lower altitudes, particularly in the zone immediately below the 

 sub-alpine and commonly known as the "montane," are found 

 treeless areas that better deserve the title of grasslands. At 

 times the transition from the forest is a gradual one, through 

 areas of savanna in which trees are scattered at rather wide 

 intervals over grass-grown fields. Such grasslands and savan- 

 nas are a well marked feature of the eastern slopes of the 

 Rocky Mountains in Colorado, and are also found in other 

 neighboring states. From their open park-like planting they 

 are popularly designated "parks." One of the best known is 

 Estes Park, some 60 miles northwest of Denver, included 

 within the limits of the recently created Rocky Mountain Na- 

 tional Park. 



It was the writer's privilege during the summer of 1914 

 to visit this Park with a class of students in field ecology and 

 also to study for some weeks a smaller mountain grassland, 

 known as Boulder Park, from South Boulder Creek, a small 

 stream traversing the park from west to east. Boulder Park 

 is 47 miles northwest from Denver upon the Mof f att Railroad, 

 has an altitude of 8880 feet, is two and a half miles long, 

 nearly a mile wide, and contains the little village of Tolland. 

 On account of the richness and variety of its vegetation it 

 was recently chosen by the University of Colorado as the site 

 of its Summer Mountain Laboratory. 



The grassland here occupies the floor of a mountain valley 

 broadened by glacial action and partially filled with the grav- 

 els of terminal and lateral moraines. These gravels have been 

 worked over so as to give the valley a comparatively level floor 

 upon which South Boulder Creek meanders in broad curves, 

 the channel often widening into shallow ponds on account of 

 the low gradient assisted by the work of beavers. Two other 

 shallow ponds or small lakes are drained into the creek. The 

 stream has intrenched itself but little and the general appear- 



