l8o UNIVERSITY OF COLORADO STUDIES 



rubber can be made. Whether the plant will be of economic value 

 needs to be determined. The plant grows to a height of from eight 

 inches to two feet, branching abundantly from the root. A non- 

 botanist might think of it as a very poor sort of golden-rod. It pro- 

 duces a number of flower heads, but they are rather small. Most of 

 the other plants growing with this one are also of the composite family. 

 Probably different kinds of Chrysothamnus and Picradenia are most 

 abundant. But throughout the drier parts of the region the number 

 of different species is few. If one looks around him in this dry region, 

 he will see, within a radius of a hundred feet, perhaps thousands of 

 plants, and yet there may be no more than a dozen different species. 

 This is always the case where environment is austere; only a few forms 

 will be well adapted to withstand the unfavorable conditions. 



In our account of these dry- country plants we should not omit the 

 shrubby pepper-grass,^ a plant of the mustard family. Everyone 

 knows the ordinary pepper-grass of door-yards and roadsides, with 

 its short stems and abundance of small white or greenish flowers, fol- 

 lowed by the flat, peppery fruits about an eighth of an inch across. 

 The sweet alyssum of the greenhouses and flower beds is familiar, 

 too. The pepper-grass at Florissant shows similarities to these two 

 plants. It has an abundance of small white flowers and the usual 

 peppery fruits. The plants grow so large that when in full bloom 

 they make a fine appearance. Along old roads and in waste places 

 they are frequently massed in large patches, or they form broad bands 

 flanking the roadway. In fact, they are such a striking part of the 

 landscape in midsummer that the Florissant region without the shrubby 

 pepper-grass would be a very different looking place. 



Next in amount after the flat, open country will come the dry hill- 

 sides. Here are scattered pines and spruces, interspersed with small 

 groves of white-barked aspen. ^ There is a greater variety of herba- 

 ceous plants than in the more open country. This is because there 

 is a greater range of conditions for plant life. Hillsides may slope to 

 east or west or north or south, and they may be cut up by gullies, expos- 



« Lepidium fonesii Rydb. • Popidus tremuloides Michx. 



