45 8 Mason . — Growth and Abscission in Sea Island Cotton . 
supplying power of the soil, and that consequently a water-shortage ensued, 
which was the immediate cause of shedding. 
Material. 
The work was carried out on the St. Vincent Experiment Station 
between June 1921 and February 1922. The first series of observations 
was made on a group of plants which were sown on June 20; this, it may 
be noted, is approximately the normal time at which cotton is planted in 
St. Vincent. The second series of observations was made on a group of 
plants which were not sown till August 27. The environmental conditions 
which prevailed during the later stages of the development of this group 
were considerably less humid than in the case of the former. 
The June-sown plants which constituted the first group consisted 
of thirty-five plants distributed at random through a plot of one-tenth of an 
acre. Two of these were rejected because of damage sustained by wind on 
September 8. The individual plants in this plot were spaced at intervals of 
four feet. A daily record was kept for each plant of the rate at which the 
main axis elongated, of the number of flower-buds and flowers produced on 
the primary fruiting branches, and of the number of flower-buds and bolls 
shed. In this group measurements of the length of the main axis were 
made every day ; the number of flower-buds and flowers produced and the 
numbers shed were not, however, observed on Sunday ; these were 
estimated as far as possible from the observations of the preceding and 
following days ; one-third of Monday’s quota was also credited to Sunday; 
the adoption of this procedure renders caution essential in interpreting 
the results. The second group was sown on August 27 and consisted of 
749 plants, spaced from 18 to 24 inches apart in rows 4 ft. wide. Daily 
measurements were made of the height of the main axis on thirty-one of 
these plants, distributed at random throughout the whole population. 
A daily record was also kept of the number of flowers produced and the 
bolls shed by all the plants. 
The Problem. 
After the work had proceeded a short time, it became apparent that 
there were three phases of the problem which merited particular attention : 
(1) the role of the physical environment in initiating abscission, (2) the 
more pronounced tendency to undergo abscission of both flower-buds and 
bolls produced during the later part of the flowering period, and (3) the 
tendency for both flower-buds and bolls to be shed when at a very early 
stage of development. 
The graph in Fig. 1 illustrates the latter tendency. The results are 
based on observations which were made on the first group of plants. The 
