1921] HARRIS—PHASEOLUS 159 
the weight of primordial leaves in the tetracotyledonous line is 
greatest when only two leaves are formed. 
A comparison of the average percentage differences for abnormal 
plants with various numbers of leaves gives the following results: 
No. of leaves Green weight Dry weight 
Bet re aa sche ls — 31.55 — 32.55 
Bere ea i ees — 20.74 — 25.54 
Aes aa Skewes —1I1.97 —16.34 
Sra ewe eis 8,60 —13.78 
Gee era ae ak m2 16 — 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 ve 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 
eee rer nena —31.55 —32.40 
Cae Ea Sirians —47.16 —50.38 
re he eg eer — 55.95 —58.12 
Lae ae ce NS 7 —63.46 —65.52 
Oe ay cee cs — 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 
