62 Wyotning' Experiment Station. 



FLORA OF THE FOOT-HILLS. 



Two kinds of foot-hills must be recognized, viz: 

 wooded and denuded. The denuded slopes are of course 

 much dryer and a large part of the year devoid of all 

 streams. These foot-hills, if stony or gravelly, are cov- 

 ered with Cercocarpus parvifoliiis, RIius tridentata, Ainel- 

 anchier alnifolia, Piirsliia tridentata — one or more in 

 varying proportion. The intervening valleys, if soil is, 

 fertile, are usually covered with sage brush. The herba- 

 ceous vegetation in such foot-hills is so varied that no list 

 can be offered here, but the following genera are well 

 represented: Draba, Astragalus, Potentilla, Actinella, 

 ErigeroJi, Senecio, Krynitckia, Phlox, Penstemon, and 

 Poa. 



If the soil contains alkali, the above-mentioned 

 shrubs give place to Grease Wood, and the herbaceous 

 vegetation largely disappears. 



The wooded foot-hills are less common, but they 

 occur at intervals in the Laramie range, much more fre- 

 quently in the Medicine Bow Mountains and the Wind 

 River range. The arboreal vegetation consists of only a 

 few species, unless one includes the Willows that skirt 

 most of the streams that flow from the higher mountains. 

 Lodge Pole Pine, Douglas Spruce, Rocky Mountain 

 White Pine, Black Cottonwood {Populus angnstifolia) 

 and more rarely Blue bpruce, Engelmann's Spruce and Ryd- 

 berg's Cotton wood (/'tf/'?/'///' J." acuminata) are the most fre- 

 quently met with. The shrubs are more varied and in- 

 clude, besides those mentioned for the drier hills, Junip- 

 erus, Prumis, Willows and Quaking Asp. The latter in 

 some places becomes a small tree and is in fact found at 

 all altitudes along streams or on hill-sides below snow 



