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 
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 
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 
