July, 1921] 
THE SEEDLING OF PHASEOLUS VULGARIS 
343 
The correlations are without exception positive in sign and of a material 
order of magnitude. They have been expressed in terms of regression on 
diagram I for trimerous seedlings and on diagram 2 for dimerous seedlings 
of the five lines.^ 
Primary Double Bundles and Mid-region of Hypocotyl 
The constants showing the relationship between number of primary 
double bundles and number of bundles in the central region of the hypo- 
cotyl, rph, are shown in the first section of table i. They are positive and 
statistically significant in all cases in both dimerous and trimerous seedlings. 
The average value of the coefficient for the five lines investigated is +.3810 
for trimerous seedlings and -I-.5086 for dimerous seedlings. 
Diagram 2 shows that in the case of the normal plants of lines 75, 93, 
and 143 a straight line represents very well indeed the changes in the mean 
number of bundles in the hypocotyl with variations in the number of pri- 
mary double bundles at the base of the hypocotyl. In line 98 the agree- 
ment is apparently not so good. This is, however, attributable to the 
fact that of the 183 plants only two have more than 5 primary bundles. 
Of these two, one plant is recorded as having 8, which is twice the normal 
number. In line 139 only plants with two classes of seedlings, those with 
4 or 5 primary bundles, are available, and since the regression line must 
connect the two means it is idle to discuss linearity of regression. 
Turning to the trimerous plants represented in diagram i , we note that 
because of the small number of plants with other than 5 or 6 primary double 
bundles the distribution of the empirical means is very irregular indeed. 
There is some suggestion of non-linearity, but the number of seedlings in 
the more extreme classes is so small for every line that little stress is to be 
laid upon them. 
In both normal and abnormal plants the slope of the regression line is 
rather steep, showing a material change in the number of bundles in the 
central region of the hypocotyl with variations in the number of primary 
double bundles at the base of the hypocotyl. 
Intercalary Bundles and Mid-region of Hypocotyl 
The correlation between the number of intercalary bundles and the 
total number of bundles in the hypocotyl, rih, are shown in the second 
2 The equations on the diagrams show the regression of the number of bundles in 
the central region of the hypocotyl, iJ, and in the central region of the epicotyl, E, on the 
number of primary double bundles, P, at the base of the hypocotyl. The empirical means 
for the hypocotyl are represented by solid dots, while those of the epicotyl are represented 
by circles. In both cases the empirical mean number of bundles for the same organ are 
connected by solid lines when the number of sections averaged was five or more, but by 
broken lines when the number available was four or less. Fortunately for purposes of 
graphical representation, the mean number of bundles in both hypocotyl and epicotyl 
• can be drawn on the same diagram. Only the lower lines in each of the five panels of the 
two diagrams require consideration for the moment. 
