98 
AMERICAN JOURNAL OF BOTANY 
[Vol. 8 
tion is from 0.8 to 0.9 bundle, or from 55 to 65 percent of the larger value in 
lines 75, 93, and 98. In line 143 the difference is only 0.4 bundle, or 36 
percent. In line 139 there is practically no difference in the standard 
deviation of bundle number in the mid-region of the first two internodes of 
the seedling. 
Table 18. Comparison of statistical constants for number of bundles in hypocotyl and epicotyl 
of same plant. Seedlings with three cotyledons and three primordial leaves 
Mean 
Standard Devi- 
ation 
Coefficient of 
V ariation 
Line 75 (N = 416) 
Epicotyl 
Actual difference 
Relative difference 
Line 93 (N = 557) 
Epicotyl 
Actual difference 
Relative difference 
Line 98 (N = 345) 
Hypocotyl 
Actual difference 
Relative difference 
Line 139 (N = 106) 
Hypocotyl 
Epicotyl 
Line 143 (N = 221) 
Hypocotyl 
Epicotyl 
i2.i9dr.O3 
i547±-04 
0.982 zb. 023 
i-355±-032 
8.06 dr. 19 
8.76dr.2I 
+3.28±.05 
26.90 
12.29rh.03 
15.65i.04 
+0.373 ±.040 
37.98 
0.922 dr. 019 
I.372dr.028 
+ 0.70dr.28 
7.50dr.I5 
8.77±.i8 
+3.36=h.05 
27-33 
12.03db.02 
14.89 d=. 04 
+o.450dr.033 
48.81 
o.532d=.oi4 
I.I52dr.030 
+ I.27dr.22 
4.42 dr. II 
7.74dr.20 
+2.86±.04 
2377 
1 1. 99 ±.05 
15.24i.08 
+0.620dr.033 
116.54 
0.694dr.032 
I.285dr.060 
+ 3.32dr.22 
5-78dr.27 
8.44dr.39 
+3.25d=.09 
27.11 
12.29 dr. 06 
l6.I0dr.08 
+0.591 ±.068 
. 85.16 
I.283dr.04I 
i.750d=.056 
+2.66dr.48 
10.44 dr.34 
10.87 dr.35 
Actual difference 
Relative difference 
+3.8id=.io 
31.00 
+0.467^.069 
36.40 
+o.43dr.49 
Basing the comparisons on the coefficient of variation, we note that the 
coefficients for the hypocotyl range from 13.0 to 17.3 percent, whereas those 
for the epicotyl range from 3.4 to 6.0 percent in lines 75, 93, and 98. Thus 
there is a difTerence of about 10 percent in the coefficient of variation of 
bundle number in the hypocotyl and epicotyl (of the normal seedlings) of 
these lines. In line 143 this difference is only —7.50 percent. In line 139 
it is only —1.69 percent. 
The statistical relationship is in full accord with the anatomical findings 
recorded above (p. 68) where it was shown that the intercalary bundles of 
the hypocotyl as they approach the cotyledonary node fuse with the (nor- 
mally 8) bundles originating by the division of the (normally 4) protoxylem 
poles of the primary root and completely lose their individuality, exactly 
six bundles emerging from the complex irrespective of the number which 
