158 ILLINOIS STATE ACADEMY OF SCIENCE 



periods, but in this case the reverse is true. Not only are 

 the full flowering periods, although separated by more 

 than a month, of nearly equal length, but individual per- 

 iods have a shorter average in the early year and there 

 are twice as many varieties having 4 and 5 day-periods as 

 in the later year. 



Fluctuations in length of varietal flowering periods are 

 common to all varieties and all years ; they are no more 

 marked in the years 1904 and 1910 — the earliest and 

 latest years — than they are in other years. Grand- 

 mother, which had a 5 day period in 1910, had a ten day 

 period in 1904, and Repka Malenka Avith an 8 day period 

 in 1910, had a 14 day period in 1904. There were 50 va- 

 rieties that had periods from 1 to 6 days longer in 1904 

 than in 1910, while 29 other varieties had periods from 

 1 to 4 days longer in 1910 than in 1904. These differences 

 suggest the operation of influences entirely apart from 

 temperatures, moisture, or other climatic conditions. 



For the 16 years of record, average varietal flowering 

 periods ranged from 5 days to 10 days ; this average was 

 5 days in 1910 and 1915, 6 days in 1908 and 1912 ; 7 days 

 in each of 6 years, 8 days in each of 3 years, 9 days in 1903 

 and 1914 and 10 days in 1907. The lengths of blooming 

 periods for individual varieties may be near together in 

 one year and widely separated in another year. There 

 is great variation in this; thus, in 1907 the minimum of 

 3 days was represented by two varieties, the maximum 

 period of 17 days by one variety, and each number of 

 days falling between 3 and 17 was represented by from 

 1 to 13 varieties ; this largest number — 13 — falling on the 

 12-day period. The total number of periods, each differ- 

 ing from its neighbor by one day, was 15; at the other 

 extreme the year 1915 has the record, for the 100 va- 

 rieties blooming in that year concentrated into 3 periods; 

 7 varieties each had a 4-day period, 57 varieties had each 

 a 5-day period, and 36 varieties had 6-day periods. 



Amount of bloom is not open to exact determination, 

 but estimates are believed to be helpful in summation of 

 characteristics of varieties and in separating those hav- 

 ing well-defined tendencies towards insufficient bloom 

 from those having the opposite tendency. Observations 



