98 



Journal of Agricultural Research 



Vol. III. No. 2 



lyalli, hulsea (Hulsea 7ianii), Alpine phacelia {Phacdia alpina), and false 

 strawberry {Sihhaldia procumbens) . Even these species occur sparingly. 



Growth does not usu- 

 , ally begin until well 



? 





p 



SO 



a 



II 



into July and ceases 

 about September i. 

 Naturally in this zone 

 any species which suc- 

 ceeds in maturing via- 

 ble seed must be vig- 

 orous and able to de- 

 velop in a short time. 



CLIMATE 



Records of tempera- 

 ture, precipitation, and 

 air humidity were kept 

 in the Canadian, Transi- 

 tion, and Hudson ian 

 zones during the main 

 grazing season, in order 

 to determine what dif- 

 ferences in the season of 

 growth they exhibit. 



TEMPERATURii. — Fig- 

 ure I shows the mean 

 temperatures of the re- 

 spective zones derived 

 from the daily maxi- 

 mum and minimum 

 during the main grow- 

 ing season of 1909. 

 While the mean tem- 

 peratures in the three 

 zones diflFered widely, 

 there is a close relation- 

 ship between the daily 

 fluctuations. In all 

 cases the mean is lower, 

 usually by several de- 

 grees, in the Hudsonian 

 zone than in the two 



lower ones, while the highest naturally comes in the Transition zone. 

 The extremes from which the mean temperature was obtained show that 



