18 
BULLETIN 1164, U. S. DEPARTMENT OF AGRICULTURE. 
margins of the bracts (fig. 18) and extension of the furrow in the 
middle of the lock far below the apex of the boll, this being 
indicated by a high mid lock furrow index (fig. 37). The occurrence 
in F 2 of numerous additional extraparental characters will be 
discussed later. 
so 
■*o 
so 
20 
/o 
%~ 
/> 
/ 
/ 
A' 
-/? 
s& 
Fig. 11.— Leaf lobe index: Frequency distribu- 
tion of Holdon X Pima F; cotton plants, by- 
grades, as used in computing the correlations. 
The ordinate figures indicate the number of 
plants as a percentage of the total population. 
60 
SO 
*o 
30 
/O 
/ 2 _? 
s e t <3 & 
%# 
// 
r, 
** 
2 
"H 
i 
/ 
\ 
/ 
f 
\ 
N 
// 
/° 
Fig. 12.— Leaf vein angle: Frequency distribu- 
tion of Holdon X Pima F 2 cotton plants, by 
grades, as used in computing the correlations. 
The ordinate figures indicate the number of 
plants as a percentage of the total population. 
The frequency distributions of F, are in the' main such as would 
be expected for characters in which several^ factors are involved. 
The resemblance to a normal frequency curve is usually evident, 
although pronounced skewness is shown by the distributions for 
several characters, especially petiole hairiness, bract connation index, 
calyx dentation, midlock furrow index, and seed fuzziness. 
go' * 
3 
*? S 
G 7* 
Q S 
so 
/fusV— 
J=r 
' / 
30 
/=> 
/o 
O 
fV 
SO 
JO 
^O 
i 
^i 
1 
4 
/ 
cr 
A* 
. 
^> 
/7 
Fig. 13.— Leaf extension index: Frequency dis- 
tribution of Holdon X Pima F 2 cotton plants, 
by grades, as used in computing the correla- 
tions. The ordinate figures indicate the num- 
ber of plants as a percentage of the total popu- 
lation. 
Fig. 14.— Leaf callus color: Frequency distribu- 
tion of Holdon X Pima F 2 cotton plants, by- 
grades, as used in computing the correlations. 
The ordinate figures indicate the number of 
plants as a percentage of the total population. 
The F 2 mode is much nearer the mean of one than of the other 
parental population in respect to the following characters, the letter 
H or P indicating the parent approached by the mode of F 2 and the 
asterisks indicating pronounced examples of displacement of the F 2 
mode in the direction of one or the other parental mean, in other 
than simple size characters : 
