9 2i] HARRIS PHASEOLUS 159 



he weight of primordial leaves in the tetracotyledonous line is 

 ,Teatest when only two leaves are formed. 



A comparison of the average percentage differences for abnormal 

 )lants with various numbers of leaves gives the following results: 



No. of leaves Green weight Dry weight 



2 -31-55 -32.55 



3 -20.74 -25-54 



4 11-97 16.34 



5- - - 8.60 -13-78 



6 - 3-10 - 7-93 



Only one sample is available for seedlings with seven primordial 

 leaves, and it is omitted from the comparison. The results for the 

 other five classes show that : 



a) The difference between the total weight of primordial leaf 

 tissue in the abnormal seedling and its normal control decreases as 

 the number of leaves in the abnormal plant increases, but that 

 throughout the entire range of variation of leaf number studied the 

 tetracotyledonous plant produces a smaller total weight of leaf 

 tissue than do normal plants of the line from which it was derived. 



b) The differences between tetracotyledonous and dicotyle 

 donous plants are always greater when the comparison is made on 

 the basis of dry weight than when it is made on the basis of green 

 weight. 



If the comparison be made on the basis of average weight per 

 leaf the following results are obtained: 



No. of leaves Green weight Dry weight 



2 -31-55 -32.40 



3 -47.I6 50-38 



4 -55-95 -58.12 



5 -63.46 -65.52 



6 67.66 69.16 



The percentage differences in average weight per leaf of course 

 increase as the number of leaves in the abnormal seedlings increases. 

 Again the greater percentage difference when dry weight serves as a 

 basis of comparison is conspicuous. The percentage of dry matter 



