HARRIS: TETRACOTYLEDONOUS RACE OF PHASEOLUS VULGARIS 235 



The results of the two determinations are in fair agreement 

 except for Classes I and II. It is exceedingly difficult to avoid 

 personal equation in distinguishing between these two classes. 

 I attribute the wide differences in percentage frequencies to this 

 cause. 



The fact that less than 5 per cent of the seedlings have axes 

 which are described as much broadened or fasciated, taken in con- 

 nection with the uncertainty of the division between the normal 

 and the slightly broadened axis, indicates that the increase in the 

 number of cotyledons and primordial leaves is not fundamentally 

 due to fasciation. It appears rather to be attributable (when any 

 modification of the stem is involved) to division of the axis or to 

 the production of axillary shoots from the cotyledons. To this 

 point I shall return below. 



Cotyledons 

 While the race has been called tetracotyledonous, the number of 

 cotyledons is really highly variable, as is shown by the totals of 

 TABLES II and III, and graphically in diagram i. 



TABLE II 



Cotyledons and leaves in less mature series 

 Leaves 



TABLE III 



Cotyledons and leaves in more mature series 

 Leaves 



