354 
AMERICAN JOURNAL OF BOTANY 
[Vol. 8, 
number of bundles in the hypocotyl and in the mean number of bundles 
in the hypocotyl associated with variations in the epicotyl. The straight 
line equations are as follows: 
Dimerous 
1 rimerous 
Line 75, 
H 
10-325 — .068E 
H 
12.055 + .oo9£ 
E 
12.347 — .ooSH 
E 
15.267 + .016H 
Line 
93, 
H 
5.736 + AOiE 
H 
1 1. 501 + .05o£ 
E 
11.494 + .065^^ 
E 
14.273 + .112H 
Line 
98, 
H 
1.374 + .648£ 
H 
11.408 + .042£ 
E 
11.388 + .07SH 
E 
12.538 + .195^^ 
Line 
139, 
H 
4-105 + .338^ 
H 
12.492 - .0335 
E 
11.254 + .103H 
E 
16.591 - .iisH 
Line 
143, 
H 
6.677 + 
H 
9.279 + .187E 
E 
11.737 + .072H 
E 
1 1. 810 -4- .349i? 
All of these lines have been drawn, but it seems unnecessary to publish 
more than three sets. 
The comparison between the empirical and the theoretical mean number 
of bundles in the epicotyls of seedlings classified according to the number 
of bundles in the hypocotyl is made for three lines on diagram 7. Con- 
versely, the comparison of the actual mean number of bundles in the hypo- 
cotyl for plants with various numbers of bundles in the epicotyl is made on 
diagram 8. 
The slight slope of the lines and the irregularity of the empirical means 
show in a very convincing manner the laxness of the relationship between 
the numbers of bundles in the central regions of hypocotyl and epicotyl. 
These results are of decided morphological significance. The profound 
difference between the correlations for the hypocotyl and for the epicotyl 
emphasizes the completeness of the loss of individuality of the bundles at 
the cotyledonary node. Whereas the number of bundles in the central 
region of the hypocotyl is quite closely correlated with the number at the 
base of the hypocotyl, there cannot be asserted to be any significant correla- 
tion in bundle number between either the base or the central region of the 
hypocotyl and the central region of the epicotyl, when we deal with seedlings 
of the same gross morphological structure. In other words, the reorganiza- 
tion of the vascular system at the node is so complete that the portion of the 
system which is above the node shows practically no relation to the portion 
which is below the node. 
Comparison of Correlation in Trimerous and Dimerous Seedlings. 
In examining the results of the preceding tables the reader may have 
noted that the coefficients for the dimerous are preponderantly higher than 
those for the trimerous plants. This result is clearly brought out in table 6 
