90 
AMERICAN JOURNAL OF BOTANY 
[Vol. 8 
A comparison of the number of bundles calculated by this formula with 
the number actually observed in the central region of the hypocotyl may 
be best made in a table of double entry. Table 13 gives the results for 
dimerous and table 14 the results for trimerous plants of line 93. The 
Table 13. Comparison of actual and theoretical number of bundles in hypocotyl of dimerous 
seedling 
Actual Number 
8 
9 
10 
IT 
12 
13 
14 
Totals 
Theoretical, 2p i 8 
12 
13 
6 
3 
34 
9 
14 
17 
3 
I 
I 
37 
10 
22 
6 
5 
35 
II 
I 
9 
9 
3 
I 
23 
12 
14 
4 
I 
20 
13 
I 
3 
4 
14 
2 
2 
Totals . . 
12 
28 
46 
22 
29 
10 
8 
155 
Table 14. Comparison of actual and theoretical number of bundles in hypocotyl of trimerous 
seedling 
Actual Number 
lO 
II 
12 
13 
14 
: c 
20 
Totals 
I 
I 
3 
5 
II 
6 
3 
I 
10 
12 
2 
102 
12 
6 
I 
I 
124 
13 
8 
3 
II 
14 
4 
I 
5 
Totals . . 
I 
9 
108 
20 
14 
2 
I 
155 
frequencies for the cases in which the number of bundles at the mid-region 
of the hypocotyl calculated from the formula agrees with the number 
actually observed are printed in blackface type. The other lines give 
roughly comparable results. 
It is clear that the number of hypocotyledonary bundles is not far from 
twice the number of primary root bundles plus the intercalary bundles. 
In rare cases the number of bundles in the hypocotyl is less than twice 
the root strands plus the number of intercalary bundles, since one of the 
root strands sometimes fails to divide. It may be, and not infrequently is, 
higher because of the appearance of extra intercalary bundles at a level 
higher than that sectioned at the base of the hypocotyl. In many cases the 
full complement of intercalary bundles has not appeared at this low level. 
In some cases it may be higher because of the secondary bifurcation above 
mentioned. 
It is worth while to give the percentage frequencies of cases in which 
the number of bundles of the central region of the hypocotyl is given by the 
formula, and for comparison the relative number of cases in which it is in 
defect and in excess. The percentages are calculated from double entry 
tables like 13 and 14. 
