Feb., I92i] HARRIS AND OTHERS — SEEDLINGS OF PHASEOLUS 
97 
The variability of bundle number, both absolute and relative, is far 
higher in the abnormal (trimerous) plants. The relative differences show 
that the trimerous plants are from 84 to 217 percent more variable than 
the dimerous in the number of bundles in the central region of the epicotyl. 
We now have to consider the relative number of bundles in the hypocotyl 
and in the epicotyl of the same plant. The constants for the normal plants 
are shown in table 17 and for the trimerous seedlings in table 18. 
Table 17. Comparison of statistical constants for number of bundles in hypocotyl and epicotyl 
of same plant. Seedlings with two cotyledons and two primordial leaves 
Mean 
Standard Deviation 
Coefficient of 
Variation 
Line 75 (N = 416) 
Hypocotyl 
Epicotyl 
Actual difference 
Relative difference 
Line 93 (N = 557) 
Hypocotyl 
Epicotyl 
Actual difference 
Relative difference 
Line 98 (N = 345) 
Hypocotyl 
Epicotyl 
Actual difference 
Relative difference 
Line 139 (N = 150) 
Hypocotyl 
Epicotyl 
Actual difference 
Relative difference 
Line 143 (N = 221) 
Hypocotyl 
Epicotyl 
Actual difference 
Relative difference 
9.49 ±.05 
i2.27dz.O2 
1.645 dr.039 
0.735 dr.017 
17.34^-42 
5-99±-i4 
+ 2.78=t:.05 
29.29 
IO.62dr.04 
12.19dr.02 
— 0.9IOdr.043 
55-31 
i.525±.03i 
0.6l5dr.0l2 
-11.35rt.44 
14.36i.30 
5.05rt.I0 
+ i.57±.04 
14.78 
9.22d=.04 
12. II db. 02 
-0.910dr.033 
59-67 
I.I97dr.03I 
0.4l6rb.OII 
- 9-31 ±-32 
12.99 d=.34 
3.44d=.09 
+ 2.89 d:. 04 
31-34 
8.II±.02 
12.15dr.02 
-0.781 d=.033 
65.24 
o.409±.oi6 
0.406 dr. 016 
- 9-55±-35 
5.04di.20 
3-35±-i3 
+ 4.04rb.03 
49.82 
8.7id=.05 
12.36rb.03 
— 0.003dr.023 
0.73 
i.i87±.038 
0.757 dr.024 
— I.69dr.24 
13.63dr.45 
6.I3dr.20 
+3.65±.o6 
41.91 
-0.430 dr. 045 
36.23 
- 7-5o±.49 
Normal and abnormal plants have in common a larger number of bundles 
in the epicotyl. The differences between the means for the two organs are 
clearly significant in comparison with their probable errors. The per- 
centage differences show that the epicotyl has from 15 to 50 percent more 
bundles than the hypocotyl. 
In the dimerous seedlings the variabilities, both absolute and relative, 
as measured by the standard deviation and coefficient of variation, are 
consistent in indicating a higher variability of bundle number in the hypo- 
cotyl. The difference is, however, very slight in line 139. 
The difference between the variability of the hypocotyl and that of the 
epicotyl in the normal seedling as measured in terms of the standard devia- 
