July 28 ,1923 
Growth of Fruiting Parts in Cotton Plants 
201 
In order to see if there was a lengthening of the square period as 
the season advanced, the data relating to the Pima variety were divided 
and compared in three successive three-week intervals. As shown in 
Table VI, the mean square period from June 15 to July 5 was 28.32 
days, from July 6 to July 26, 31.11 days, and from July 27 to August 
15, 31.43 days. From these data it appears that the square period 
is shorter early in the season than later, but that the increase of the 
third three-week interval is not significantly greater than that of the 
second three-week interval. This relation could not be determined in 
the other varieties, since the data were not recorded for sufficiently long 
intervals. 
Table VI. —Mean square period for three 3-week interval of Pima at Sacaton, Ariz., 
1921 
Squaring period. 
Period I, June 
Period II, July 6 
Period III, July 
15 to July 5. 
to July 26. 
27 to Aug. 15. 
Mean number of days. 
28. 32 ±0. 115 
31. II±0. 067 
31. 43 ± alI S 
A further comparison of the mean period required for the development 
of squares on the successive internodes of the fruiting branches was 
made on the Pima at Sacaton in 1921. These data are summarized 
and presented in Table VII. The mean square period at each node 
is seen to increase slightly after the second node. This increase, how¬ 
ever, is regarded as being due to the fact that the squares on the outer 
internodes were produced later, and it has been previously shown that 
the later squares have a longer square period regardless of their position 
on the fruiting branches. From these data there is no significant evi¬ 
dence that the square period is longer because the square is produced 
at the outer nodes, toward the end of the branch. This is evident when 
the periods for squares of first nodes are compared with periods for 
squares of fifth nodes that appeared on the same dates. 
Table VII. —Mean square period for the successive internodes of the fruiting branches on 
Pima, Sacaton, Ariz., igsi 
Fruiting branch internode No.— 
1 
2 
3 
4 
5 
Mean number of days. 
29.4 
29.4 
30. I 
3 °- 7 
31 * i 
GROWTH OF THE FLORAL BUD 
A daily record of the size of floral buds was made on the Lone Star 
variety at Greenville, Tex., in 1922. The size of the bud was deter¬ 
mined by depressing one bract of the young square and measuring the 
length of the bud from the base of the calyx to the tip of the corolla. 
Measurements were started when the bracts of the square were about 
