154 BOTANICAL GAZETTE [SEPTEMBER 



In work with the variants in normal lines of beans there is no . 

 difficulty whatever in distinguishing primordial leaves from those 

 subsequently formed, except occasionally in extreme variations 

 involving stem characters such as would ordinarily be classed as 

 fasciations. In the case of the tetracotyledonous race, however, it t 

 is often difficult to distinguish between true primordials (those 

 formed in the seed) and the simple leaves (not compound) formed 

 subsequently. This difficulty was noted in the first paper on the 

 tetracotyledonous race, and two series of countings at different 

 stages of development of the seedling were made to determine to 

 what extent personal equation may affect the constants for number 

 of primordial leaves. 



For practical reasons it was not feasible to count the leaves of the 

 tetracotyledonous plants used in these experiments immediately 

 after germination. Countings, therefore, were made just before 

 the samples were taken. The numbers recorded are those of leaves 

 which were regarded as certainly primordial. Those which from 

 their color or texture appeared to be of subsequent development 

 were omitted. In this race filaments are of rather frequent occur 

 rence. These are probably morphologically much reduced leaves, 

 and were also disregarded. Thus the number of primordial leaves 

 is probably on the average slightly under rather than over the true 

 number for the series as a whole. Since we are primarily concerned 

 with a comparison between definite types of seedling classification 

 with respect to number of leaves, this procedure can introduce no 

 sensible error into the results. 



Because of some uncertainty as to the leaves which were to^ 

 be considered primordial and the considerable variation in the&amp;gt; 

 stages of development of the compound leaves in the tetracotyle 

 donous plants, it did not seem feasible in the majority of determina 

 tions to consider separately the weight of tissue formed by the* 

 compound leaves. This, however, has been done indirectly in the 

 case of certain samples based on the plants as a whole. 



Data 



The data fall in three groups: a series of weighings of primordial 

 leaves of plants unclassified with respect to number of primordial 

 leaves; a series of weighings of primordial leaves of plants classified 



