Stout & Boas: STATISTICAL STUDIES IN CICHORIUM 389 
TABLE 10 
RANGE OF VARIABILITY FOR SUCCESSIVE 20-DAY PERIODS OF BLOOM. ЮАТА FOR Fi 
3-YEAR-OLD PLANTS (REPORTED IN TABLE I8). DATA FOR Ез I-YEAR-OLD PLANTS 
(REPORTED IN TABLE 20) 
| Range of variability Difference | Number of plants 
First 20 days | 30—14 | 16 | 107 
Secondo seo | 27-10 17 107 
Tiu bm | 25-12 13 | 107 
Hi ЖОНЫП С! 25—10 ї5 от 
th d ЖУ, 23-10 13 76 
Sixth 5 24-11 13 50 
Seven реда 22-12 10 | 18 
First 20 days 33-10 | 23 | IIO 
Seco B 24- 9 | 15 | 97 
Е pides 23—11 | т2 | 78 
Fourth “+ 23-10 p 13 | 39 
Fifth ы 20—12 8 | I2 
This table shows that the lowest flower number on a plant 
may appear in the first or second twenty days of the blooming 
period while the highest number appears only in the beginning of 
the season and decreases as the season advances. This must, of 
course, result in a smaller variability for the end of the season and 
also explains why there is such a marked negative correlation 
between rate of decrease and length of the blooming period. 
The period of bloom for plants in the first year of growth is 
shorter than in the succeeding years. There is, however, a 
similar negative correlation between rate of decrease and length 
of blooming period, as in the older plants discussed above. For 
the behavior of plants in the first year of bloom there are data on 
110 of the Ез plants, all blooming in the same year (1915). The 
plants, for convenience, have been grouped into five groups, each 
group blooming twenty days longer than the preceding. As 
shown in TABLE 20 the same sort of differences appear in successive 
twenty-day periods as in the older plants, that is, the differences 
are less or there may even be an increase in the later periods. 
The variabilities for the Ез plants are given in the same way 
as for the F, plants, and here too the o’s are the greatest for the 
first twenty days. 
From the foregoing discussion, it is clear that there is less dif- 
ference between the averages and that the variabilities are lower 
for twenty-day periods after the first eighty days for the three- 
