Phonological Observations in Canada. 77 



more rapidl}^ this year than last year, while in May or a 

 portion' of May it may be advancing less rapidly according 

 to the varying balance of the meteorological conditions 

 affecting the organisms. Averages of the dates of early 

 flowering plants, for instance, during one season might be 

 compared with those of another season. Averages of a 

 normally later series of flowers might be similarly treated. 

 But to compare one spring with another spring, a series of 

 typical flowers normally flowering in succession from the 

 earliest date to the latest might be taken. Such an 

 average or mean for comparison we might for convenience 

 call a phenological norm or phenochron (a phenological time 

 ordinate). Phenochrons for comparison or for the plotting 

 of phenological curves should be based on the same num- 

 ber of observations taken at the same stations under 

 similar conditions, and if they are to correctly represent 

 any district of considerable extent, the stations should be 

 symmetrically distributed. The following table, compiled 

 from the observations taken by members of the Botanical 

 Club, is defective in two respects, although we should 

 grant that tlie observations individually taken were all 

 correctly made on exactly the same lines. Twenty objects 

 most generally observed were selected from the schedules, 

 and we have a series of seven years, from 1892 to 1898. 

 But the average dates for 1892 were based on observations 

 made at nine stations, none of which were in the eastern 

 half of the province or towards the extreme north. In 

 later years there was a less number of southern and a 

 greater number of northern stations. This illustrates the 

 defect of the asymmetry of the distribution of stations. 

 Again, while in 1892, for instance, the whole nine stations 

 made observations on all or many of these 20 phenomena, 

 there were many other phenomena observed at only a few 

 stations. This defect is practically one of asymmetry 

 also, for as the observation of the migration of birds was 

 omitted in the most northern station this year, the average 



