[LLOYD] ABSCISSION OF FLOWER BUDS 59 
practically equal; otherwise and usually less. This finding permits us 
to look for the cause leading to a maximum shedding response within 
six days previous to the date on which such a maximum falls. We 
cannot expect a high frequency of shedding referable to a given 
stimulus later than six days after its occurrence, except at a time 
when the numbers of young bolls are reduced, due to the cessation 
of flowering and the consequent increase in the abscission period be- 
cause of the greater proportion of older bolls as already indicated. 
THE MARCH OF SHEDDING 
Proceeding from the above conclusions, the march of shedding 
for each of four years, 1906, 1907, 1911 and 1912, at Auburn, Ala., 
has been examined and the following general conclusions drawn: 
There is always observable a steadily increasing total shedding 
rate, first of squares, and, as the bolls appear, of these also. The 
cessation of growth is the immediate limitation of square shedding; 
of flowering, that of bolls, having due regard to the ultimate shedding 
of older bolls. At first the rate of shedding is relatively less, regarding 
the number of flowers as a standard, and later, relatively greater. 
The adjustment of the plant to its environment is relatively better 
earlier in the season, and worse later on. So far as it has been possible 
by elimination to determine the cause of this increasing maladjust- 
ment, it would seem most probable that it is due to a condition which 
itself is constantly changing from a more to a less favourable with 
respect to the plant. This appears with a high degree of certainty to 
be the gradual reduction of the soil-moisture content of the deeper 
reaches of the soil, that, namely which is in contact with the lower 
root-system. That such a reduction of soil-moisture actually takes 
place during the growing season is shown by records of the levels of 
well-water, in which it appears that the water-table is gradually 
lowered during the spring and summer, and does not begin to rise 
appreciably till the advent of winter rains. If all other environmental 
conditions other than this, namely, the deeper soil-moisture, were 
constantly at their optimum for the plant, the steady lowering of the 
deep-soil-moisture would put an increasingly more stringent tax on 
the plant, causing increasingly greater shedding rates relative to the 
number of flowers, or, what is the same thing, to the size of the plant. 
The shedding rates do not, however, increase uniformly. As a 
matter of fact there are always fluctuations in these rates, indicating 
corresponding changes in the character of the remaining environment, 
now more favourable for the plant, now less. Changes which combine 
to increase the loss of water from the plant increase the shedding rates, 
