postelsia 51 



kind and a few of another there may 

 be a hundred or a thousand individuals 

 of a species crowded together. At 

 flowering time these masses are most 

 striking in appearance. Whole hillsides 

 or great gullies will be blue with 

 Pentstemons or yellow with Arnicas. 

 Masses of Arnica plants in flower on 

 the foothills can be seen for long 

 distances as distinct yellow patches. 

 These plants are not to be considered 

 as exceptional. Many other species 

 also occur in large masses. This is 

 especially the case with early flowering 

 species. The months of May and 

 June make the growing season for 

 most plants. In those months the 

 colors of the hills and gulches change 

 very quickly. The various species blos- 

 som one after another in quick suc- 

 cession. After the summer solstice the 

 green hills and mesas change to brown, 



