260 FRANCIS RAMALEY 



bank next to the meadow association. Scattered plants occur 

 also in the various societies of the dry grassland. 



Vaccinimn society. Vaccinium caespitosum, Androsace puher- 

 ulenta, Carex siccata. This society develops on east exposures 

 in snow-drift areas where the ground is covered with snow until 

 late in the Spring, and where most of the dry grassland plants 

 are unable to grow because of the short season. The Vaccinium 

 is scarcely 5 cm. tall. The standing of this community is some- 

 what uncertain; it might with propriety be designated as a bit 

 of forest undergrowth from the sub-alpine regions of higher 

 altitudes. It has very little ecological affinity with the ordinary 

 dry grassland. 



Vegetation of Fairy Rings. Many fairy rings of the mushroom 

 Tricholoma praemagnum^'^ are scattered about through the dry 

 grassland (fig. 5). Within the ring there is often a considerable 

 growth of Artemisia frigida, and at its margin Mertensia bakeri, 

 Cerastium occidentale and Sedum strenopetalum are prominent. 



ENVIRONMENTAL FACTORS 



The chmate of Boulder Park is severe. Summers are short, 

 winters are long. There is much wind, especially in winter. 

 Although the precipitation in winter is considerable, much of the 

 snow is blown off from exposed slopes and ridges so that these 

 are bare for weeks at a time during cold weather. The annual 

 rainfall is probably about 28 inches. The largest part of the 

 precipitation comes as snow, much of this during April and May. 

 In summer there are frequent hght showers, the moisture from 

 which may not penetrate more than 1 or 2 cm. Mean tempera- 

 tures for June, July and August are probably about 50°, 57° 

 and 55° respectively and the mean annual temperature about 

 40°F. All these figures are approximate since exact data are 

 available for temperature only and during the summer months 

 of two seasons. The climate may, however, be judged with a 



1" Ramaley, Francis, Mushroom fairy rings of Tricholoma praemagnum. Tor- 

 reya, In press. 



