288 



and 3.5 for the oak. For all these he adopts 4 days, as in previo,as 

 years. 



Lea-fing. — The mean temperatures at the dates of leafing for 1886 

 and 1887 are given, as follows : 



Data for 1886 and 1887. 



The sums of temperatures received by these plants from the last 

 freezing period up to the time of leafing, and counting from 0° C. as 

 the initial temperature, are as follows : 



The -flowering of the lilac, chestnut., elder., and linden. — A new 

 determination of the rate of retardation of flowering for these plants 

 gives 4.7, 4.2, 4.4, and 3.8 days per 100 meters, respectively, for 

 which, as before, 4 days is adopted. The mean temperatures at the 

 times of flowering for the years 1886 and 1887 are as follows : 



The sums of temperatures above 6° C, counting from the last freez- 

 ing period and up to the date of flowering, for the years 1886 and 

 1887 are as follows: 



