32 ILLINOIS STATE ACADEMY OF SCIENCE 



brightly colored and generally full size. Characteristic 

 species are the mountain dryad, mountain pink, several 

 saxifrages, red and yellow stonecrops, dogtooth lily, 

 cinquefoil, mountain sorrel, mountain forget-me-not, and 

 wild candy tuft. These plants continue in very open 

 stand as far as any gravelly soil can be found. Among 

 those which are found at the highest levels are the dryad, 

 mosspink, a saxifrage, a hedysarum, a dandelion, and 

 duckweeds. On the bare rock surfaces there is a pro- 

 fusion of lichens, predominantly greenish-gray, but also 

 black and white, brown, lavender and even yellow and 

 red. 



PLANT COMMUNITIES OF ALPINE PAEK. 



Near the summits of the mountains, small level tracts 

 are occasionally found which may be called mountain 

 parks. These contain slight depressions in which snow- 

 banks accumulate and frequently remain until late in the 

 summer. The vegetation of these parts resembles the 

 tundra of the arctic regions interspersed with scattered 

 clumps of stunted conifers. (Fig. 3.) In the drier por- 

 tions of the tundra, the main groundcover consists of 

 grasses and sedges with such characteristic flowering 

 plants as the red and white heathers {Pliyllodoce), the 

 shooting star, the Rocky Mountain laurel, the dwarf 

 willow, the alpine speedwell, fringed gentian, Indian 

 warrior, and rock cress. 



The snowbanks have a different and a very character- 

 istic vegetation. In the early part of the season, the dog- 

 tooth lily grows around the edges of the snow, even com- 

 ing up through the snow and blooming before it has melt- 

 ed away. When the snow has completely melted, the bot- 

 tom of the little hollow is found to contain not the dog- 

 tooth lily but the alpine spring beauty. The conifer 

 clumps are usually found on the shallow dry soil which 

 overlies rock ledges and they follow the outlines of the 

 buried rock ridges. The species include fir, spruce, the 

 white-bark pine, and the Rocky Mountain juniper. 



On the sides of the parks near the mountain slopes, the 

 rock ledges often protrude through the scanty cover of 

 soil and here the plant communities are quite different. 



