418 SEMI-CENTENNIAL OF TORREY BOTANICAL CLUB 
general habit of growth of each was quite uniform in 1913, 1914, 
and 1915. The parents E; and E» were in their second year of 
growth in 1913. During the winter of 1914-1915, the plant Es 
was destroyed by pine mice. In the early spring of 1915 the roots 
of each plant (А, C, and E;) were divided in two and grown as two 
plants, from which data were taken separately. The data for 
these various plants and for the hybrid generations are tabulated 
in TABLES 38 and 39. 
It is clear from these comparisons that there is a rather close 
agreement in the behavior of a plant in successive years with re- 
spect to the production of flower number as determined by the 
calculated values for а. The nature of the development of a plant 
and the many factors contributing to fluctuations in development 
and production of flower number are such that exact agreement is 
not to be expected. The variations in the value of a for any one 
plant from year to year follow a rather uniform course. The 
value is, as a rule, lower for the first year of bloom than for the 
second and there is a further slight increase in the third year. 
The behavior of a plant is more uniform in the second and 
third years of growth. The data for plants А, C, Es, and Ex 
indicate that such is also the case in later years. 
TABLE 38 
FLOWER NUMBER PER HEAD (d) IN THREE SUCCESSIVE YEARS OF PLANTS THREE OR 
MORE YEARS OLD. DATA FOR 1013, I914, AND 1015 
Value оға 
Plant 
1913 1914 1915 
Жазу 10.2 10.2 18.6 
19.3 
Буы E 19.3 18.0 18.5 
17.6 
раты 215 21.8 23.0 
21.8 
ЖА ра 20.6 20.8 20.8 
20.6 
ЕМ opie 23.0 23.6 dead 
TABLE 39 gives the values of a for plants of different ages, for 
the entire Е, and Е, population and for the various lines of descent. 
For the Еу plants, as a group, the average the first year is 18.8; 
for the second year is 20.6 and for the third is 21.0; the average 
