Feb., I92i] HARRIS AND OTHERS — SEEDLINGS OF PHASEOLUS 8l 
The variability, both absolute and relative, of the number of bundles is 
higher in dimerous than in trimerous plants. It is conspicuously higher 
in lines 75, 93, and 98. Thus the standard deviations for the trimerous 
plants range from 0.37 to 0.60 in the three lines as compared with 0.91 to 
1.09 in the dimerous controls. The relative differences show that the 
variability of the trimerous plants is from 45 to 60 percent less than that of 
the dimerous plants. In the case of line 143, however, the difference 
between the standard deviation of the two types of seedlings is very small — 
less, indeed, than the probable error of the difference. Practically the 
same condition is found in line 139. 
The coefficients of variation show that the trimerous plants have a 
variability in bundle number which is from 5.1 to 10. i percent of the mean 
number of bundles, whereas the dimerous controls have a variability which 
is from 8.2 to 22.4 percent of the average number. In lines 75, 93, and 98 
the difference between the two types is much more conspicuous than in lines 
139 and 143. 
Since in practically all cases, however, the primary double bundles 
have already clearly become two strands at the point where the intercalaries 
appear, it probably gives us a better conception of total bundle number here 
to count each primary bundle as two, and to add thereto the number of 
intercalaries. The actual and the percentage distribution according to this 
method are shown in table 9. Lines 75, 93, and 139 are represented in 
Table 9. Total number of bundles at base of hypocotyl in trimerous and dimerous seedlings. 
Primary double bundles are counted as two 
■ I « 
9 
10 
1 
" i 
.3 
13 
14 
15 
16 
17 
Total 
Line 75 
Trimerous . . 
2 
8 1 
109 
12 
10 
I 
142 
Percent . . 
1.41 
5.63 i 
76.76 
8.45 
7.04 
0.70 
Dimerous. . . 
69 
30 
23 
8 1 
8 
4 
142 
Percent . . 
48.59 
21.13 
16.20 
5.63 1 
1 
5.63 
2.82 
Line 93 
Trimerous . . 
5 
10 1 
124 
II 
5 
155 
Percent . . 
3-23 
6.45 
80.00 
7.10 
3.23 
Dimerous. . . 
34 
37 
35 
23 
20 
4 
2 
155 
Percent . . 
Line 98 
Trimerous . . 
21.93 
23.87 
22.58 
14.84 
12.90 
2.58 
1.29 
I 
4 
6 
161 
10 
I 
183 
Percent . . 
0.55 
2.19 
3.28 
87.98 
5.46 
0.55 
Dimerous. . . 
97 
43 
29 
10 
2 
I 

183 
Percent . . 
53.01 
23.50 
15.85 
5.46 
1.09 
0.55 
0.55 
Line 139 
Trimerous . . 
I 
4 
4 
92 
5 
106 
Percent . . 
0.94 
3.77 
3-77 
86.79 
4.72 
Dimerous. . . 
138 
9 
I 
2 
150 
Percent . . 
92.00 
6.00 
0.67 
1.33 
Line 143 
Trimerous . . 
2 
3 
15 
31 
134 
25 
5 
4 
I 
I 
221 
Percent . . 
0.90 
1.36 
6.79 
14.03 
60.63 
11.31 
2.26 
1.81 
0.45 
0.45 
Dimerous. . . 
150 
55 
9 
5 
I 
I 
221 
Percent . . 
67.87 
24.89 
4.07 
2.26 
0.45 
0.45 
1 
! 
1 
