402  SEMI-CENTENNIAL OF TORREY BOTANICAL CLUB 
The performances of the different branches of the plant shown 
in TABLES 24 and 26 were more similar than those of the different 
branches of the plant reported in TABLES 25 and 27. The graphs 
in the latter case overlap and cross and the graph for the plant asa 
whole is less in agreement with that of a single branch. 
From such studies of the individual behavior of the different 
branches we gain some clue to the immediate causes of the irregu- 
larities which appear in the data collected from day to day, and 
of the irregularities that appear in the rate of decrease in the num- 
ber of flowers per head. Differences in the relative development 
of the various branches, and the number of branches produced, 
have a marked influence on the average flower number observed 
from day to day and in the corresponding rate of decrease. 
It is apparent that the irregularities are due chiefly to varia- 
tions in behavior of the different branches during the first twenty 
or twenty-five days of blooming and ате chiefly due to the number 
of branches and to the rate with which these come into bloom. 
The averages for the whole plant may show no decrease, a very 
slight decrease, or even a slight increase (see TABLE 27) during the 
period of first blooming, due to the fact that day after day for a 
longer or shorter time new branches begin to bloom all with a 
high flower number per head. If, however, a considerable number 
of branches have been in bloom for some time and are showing a 
marked decrease in flower number per head when late branches 
come into bloom, the higher flower numbers of the latter will for 
a time retard the rate of decrease. The irregularities occur chiefly 
at the beginning and the end of the period of blooming. In all 
cases the rate of decrease is less until all branches are in bloom. 
It would appear that the most typical development of a plant 
is such that the branches from the oldest to the youngest show 
characteristic differences in the number of flowers per head and 
in the rate of decrease, which may be somewhat analogous to the 
behavior of a plant at different ages. The uppermost branches 
in comparison with the lower branches of the same plant are, as a 
rule, smaller, have fewer heads, bloom for a shorter period, and 
show less decrease in flower number. While the variations in 
and among the various branches of different plants considered as 
wholes are so pronounced that a perfect or exact type of develop- 
