July 28, 1923 
Growth of Fruiting Parts in Cotton Plants 
197 
The data from Sacaton and Charleston were obtained under condi¬ 
tions of unchecked growth, and no seasonal variation in the rate of 
branch formation was shown in the records. At Greenville, however, 
the development of the plants was stopped by a drought in July and 
August. The checking effect of this drought was apparent late in July, 
and all squares produced after that period were shed before the flowering 
stage was reached. Yet the interval between first blooms of successive 
branches at the end of the flowering period was not consistently longer 
than the interval between blooms early in the season. This indicates, 
that a reduced rate of growth of the plants did not materially influence 
the rate of appearance of fruiting branches during the flowering period. 
It is possible, however, that if the subsequent squares had reached the 
flowering stage, a definite increase in the interval between blooms might 
have been found. 
The data on Lone Star grown at Sacaton, Ariz., and Greenville, Tex., 
show the widest difference in the mean interval between the appearance 
of fruiting branches. The data on the other varieties show a close agree¬ 
ment in the rate of production of fruiting branches. That such uni¬ 
formity in rate of production could be obtained under widely different 
conditions of soil, climate, and moisture seems remarkable. 
GROWTH OF FRUITING BRANCHES 
The fruiting branch is formed by the development of a series of joints, 
or internodes, each bearing a floral bud, or “square.” As described 
previously in this paper, the first indication of the fruiting branch is 
the appearance of a minute square and its subtending leaf, inclosed 
between the stipules of the leaf on the axis. Following the appearance 
of the square, the first internode of the fruiting branch begins to lengthen, 
carrying the square and its leaf away from the main stalk. As growth 
proceeds in the first internode of the fruiting branch, the bud which will 
form the second node slowly develops until the second square and 
subtending leaf may be seen. This procedure is followed throughout 
the growth of the fruiting branch, the preceding node growing for a 
certain interval before the next square appears. 
Different types and varieties of cotton differ in the length and the 
number of internodes of the fruiting branch. The rate of production 
of squares, however, is the factor of greatest importance to be con¬ 
sidered, particularly under boll-weevil conditions. 
In the season of 1921 at Sacaton, Ariz., the date of appearance of 
each square on each branch was recorded on 10 plants each of the 
following varieties: Lone Star, Durango, Acala, and Pima Egyptian. 
From these records it is possible to find the average number of days 
between the appearance of successive squares on any branch or at 
any group of internodes. 
A similar series of records was obtained in 1922 on the Sea Island 
and Meade varieties of cotton grown at Charleston, S. C. Data were 
obtained on the Lone Star variety at Greenville, Tex., the interval 
in this case being determined by the number of days between blooms 
on successive internodes. 
These data, presented first in Table II, show an average of about 
six days between the appearance of successive squares for all the fruiting 
branch internodes of the plant. It will be noted that the production 
of new squares on the fruiting branches proceeds at Sacaton at the same 
48110—23-3 
