ct., 1921] 



HARRIS AND OTHERS PHASEOLUS VULGARIS 



379 



heir lower number of primary double bundles and possibly by a higher 

 lumber of intercalary bundles. They cannot be said to differ from the 

 rimerous seedlings in the total number of bundles at the base of the 

 [lypocotyl. 



Central Region of Hypocotyl 



For the number of bundles in the central region of the hypocotyl we 

 ave the fundamental frequency distributions given in table 3. Considering 

 he mean number of bundles in table 4, it appears that the number of bundles 

 i the central region of the hypocotyl of hemitrimerous plants is slightly 

 Wer than that found in trimerous seedlings in four of the six lines available, 

 he differences are, however, small and would not for the most part be 

 onsidered significant in comparison with their probable errors. The 

 undle number of hemitrimerous plants is in every case distinctly higher 

 han that of dimerous plants at this level, and these differences are con- 

 picuous and unquestionably significant. Thus in hypocotyledonary struc- 

 ure the hemitrimerous seedling is very close indeed to the trimerous but 

 erhaps shows a slight deficiency in bundle number. 



This result is not surprising in view of the fact that so far as the coty- 

 jdonary node and lower portions of the axis are concerned the external 

 orm of hemitrimerous and trimerous seedlings is essentially identical. 



Central Region of Epicotyl 



If a differentiation between the hemitrimerous and trimerous seedlings 

 btains anywhere, one would expect to find it in the epicotyledonary region, 



TABLE 3. Distribution of number of bundles in central region of hypocotyl 



