174 BROOKLYN BOTANIC GARDEN MEMOIRS 



Notwithstanding these two sources of difificulty in basing con- 

 clusions on relative amount of dry substance, there seem clear evi- 

 dences that the abnormal plants produce relatively as well as abso- 

 lutely less dry matter than the normals. 



In the case of the primordial leaves, there are 20 samples in which 

 the relative dry weight is lower in the abnormal plants as against 3 in 

 which.it is higher. In the first compound leaf there are 15 samples 

 in which the relative weight in the abnormal plants is lower, as com- 

 pared with 8 in which it is higher than the normals. 



The average percentage content of dry substance in the primordial 

 leaves of the abnormal seedlings is 6.509 as compared with 6.779 in 

 the normal controls, or a difference of —0.270. The average percent 

 of dry matter in the first compound leaf is 8.030 in the abnormal as 

 compared with 8.080 in the normal, or a difference of —.050 percent. 



Concluding Remarks 



The constants recorded in this paper are the results of one of the 

 phases of an attempt to determine the nature of the relationship 

 between morphological and physiological variations in plants. 



The results of the criteria applied are beautifully clear and con- 

 sistent. 



Seedlings of Phaseolus which show one of the smallest definite 

 structural variations, the slight vertical separation of the two coty- 

 ledons in their insertion on the axis, are differentiated from the struc- 

 turally apparently normal individuals in their physiological as well 

 as in their morphological characteristics. 



This is shown by the facts that the morphologically abnormal 

 plants produce a smaller weight of green leaf tissue, a smaller actual 

 weight of dry substance in the leaf tissue, and a smaller relative weight 

 of dry substance. This is true for both the primordial leaves and 

 the first trifoliate leaf. 



