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 ani theoretical number of bundles in hypocotyl of dimerous 



seedling 



TABLE 14. Comparison of actual ani theoretical number of bundles in hypocotyl of trimerous 



seedling 



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. 



