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AMERICAN JOURNAL OF BOTANY 
[Vol. 8 
variability ranging from -4.7 to -8.0 percent. In line 139 the coefficient of 
variation for trimerous seedlings is 5.47, whereas that for dimerous seedlings 
is 3.48. In line 143, the coefficient of variation for trimerous seedlings is 
10.01, whereas that for dimerous seedlings is 7.75. Thus the relative 
variability in these two lines is greater in the trimerous than in the dimerous 
seedlings. 
B. Intercalary Bundles. The distribution of the number of intercalary 
bundles (considered alone) in the base of the hypocotyl is shown in table 5. 
Fig. 14. Percentage frequency distribution of number of intercalary bundles at base 
of hypocotyl in dimerous (solid dots) and trimerous (circles) seedlings. 
The graphs in figure 14 show that for both dimerous and trimerous 
seedlings no intercalary bundles is the modal condition. In both cases 
the distribution is wholly skew. The normal and the abnormal seedlings 
of lines 75, 93, and 98 differ conspicuously, however, in that the percentage 
of seedlings with no intercalary bundles is much higher in the trimerous 
seedlings, while, conversely, the percentage of seedlings with from i to 5 
intercalary bundles is much higher in the dimerous plants. These dif- 
ferences are not found in lines 139 and 143. As a matter of fact, the per- 
centage of seedlings with no intercalary bundles is slightly, but perhaps not 
significantly, higher in the dimerous seedlings of line 139. In both lines 
139 and 143 the number of seedlings with i or 2 intercalary bundles is very 
small indeed in both trimerous and dimerous series. The two lines are 
essentially alike in this regard and line 143 only is represented on the 
diagram. 
