160 BOTANICAL GAZETTE [SEPTEMBER 



in the seedlings of this extremely abnormal race is shown in com 

 parison with the normal control plants in table III. The results 

 are self-explanatory. Without exception, in the twenty-three 

 samples representing weighings of 9958 leaves of abnormal and 

 4668 leaves of normal plants, the percentage of dry matter is lower 

 in the abnormal than in the control series. A study of the averages 

 for the individual groups of seedlings, classified with respect to 

 primordial leaf number, does not suggest a significant difference in 

 the percentage of dry matter in the different classes of seedlings. 

 Probably a far larger series of weighings would be required to 

 bring out such a differentiation if it exists at all. 



TOTAL WEIGHT OF EPICOTYLEDONARY TISSUE IN PLANTS OF 

 TERATOLOGICAL AND NORMAL RACES. In the foregoing discussion 

 comparisons were limited to the weight of primordial leaves. This 

 was done because of the difficulty of securing leaves subsequently 

 formed in comparable stages of development in the normal and 

 teratological seedlings. It seemed desirable to supplement these 

 studies by the determination of the total weight of tissue produced 

 by the two races. The results for a comparison of the total w r eight 

 of tissue produced above the cotyledonary node by tetracotyle- 

 donous plants and their normal control of line 139, are shown under 

 the heading &quot;epicotyl&quot; in the fundamental tables of data. 



The constants show that without exception the green weight and 

 dry weight per plant and percentage dry matter are higher in the 

 normal than in the tetracotyledonous plants. The percentage 

 differences range from 7. 6 to 29. 4 in the case of green weight, 

 and from 10 . i to 30 . 5 in the case of dry weight. The differ 

 ences in percentage of dry matter range from 0.036 to 0.249. 

 The average weight of green tissue per plant is 1.4447 f r tne 

 abnormal and i . 8088 for the control series, or a difference of o . 3640 

 gm. The average dry weight per plant is o . 1093 for the abnormal 

 and o . 1384 for the normal seedling, or a difference of o .0291 gm. 

 The average percentage difference for the green weight is 18.96} 

 while for dry weight the difference is 20.30. The percentage of 

 dry material in the abnormal seedling is 7 . 6448 as compared with 1 

 7.7740 in the control, a difference of 0.1292. 



