Oct., 1921] HARRIS AND OTHERS — PHASEOLUS VULGARIS 
379 
their lower number of primary double bundles and possibly by a higher 
number of intercalary bundles. They cannot be said to differ from the 
trimerous seedlings in the total number of bundles at the base of the 
hypocotyl. 
Central Region of Hypocotyl 
For the number of bundles in the central region of the hypocotyl we 
have the fundamental frequency distributions given in table 3. Considering 
the mean number of bundles in table 4, it appears that the number of bundles 
in the central region of the hypocotyl of hemitrimerous plants is slightly 
lower than that found in trimerous seedlings in four of the six lines available. 
The differences are, however, small and would not for the most part be 
considered significant in comparison with their probable errors. The 
bundle number of hemitrimerous plants is in every case distinctly higher 
than that of dimerous plants at this level, and these differences are con- 
spicuous and unquestionably significant. Thus in hypocotyledonary struc- 
ture the hemitrimerous seedling is very close indeed to the trimerous but 
perhaps shows a slight deficiency in bundle number. 
This result is not surprising in view of the fact that so far as the coty- 
ledonary node and lower portions of the axis are concerned the external 
form of hemitrimerous and trimerous seedlings is essentially identical. 
Central Region of Epicotyl 
If a differentiation between the hemitrimerous and trimerous seedlings 
obtains anywhere, one would expect to find it in the epicotyledonary region, 
Table 3. Distribution of number of bundles in central region of hypocotyl 
8 
9 
10 
ir 
12 
13 
14 
15 
16 
17 
18 
20 
24 
Total 
Line 29 
56 
3-3 
I 
6 
41 
I 
3 
3 
T 
3-2 
2 
6 
8 
21 
2 
2 
I 
I 
43 
2-2 
67 
21 
9 
2 
99 
Line 75 
3-3 
I 
3 
5 
36 
292 
40 
29 
5 
I 
4 

416 
3-2 
2 
3 
13 
51 
16 
14 
2 
2 
103 
2-2 
177 
131 
103 
46 
31 
14 
II 
I 
3 
I 
519 
Line 93 
3-3 
8 
32 
382 
82 
38 
12 
I 
557 
3-2 
4 
6 
17 
8 
7 
I 
43 
2-2 
36 
93 
170 
107 
96 
40 
18 
J 
2 
563 
Line 98 
3-3 
I 
6 
12 
297 
21 
8 
345 
3-2 
3 
7 
25 
3 
1 
I 
I 
43 
2-2 
125 
126 
83 
37 
II 
5 
I 
388 
Line 139 
3-3 
4 
8 
84 
6 
3 
I 
106 
3-2 
I 
3 
4 
II 
19 
3 
I 
42 
2-2 
269 
23 
7 
4 
I 
I 
305 
Line 143 
3-3 
2 
I 
1 1 
14 
136 
21 
25 
6 
3 
I 
I 
221 
3-2 
17 
19 
54 
4 
8 
5 
4 
114 
2-2 
263 
83 
47 
17 
4 
3 
2 
420 
