HARRIS: TETRACOTYLEDONOUS RACE OF PHASEOLUS VULGARIS 243 



For more mature series — 



/ = 3.004 + .492 c 

 c = 3-513 + -050/ 



For both series combined — • 



I = 3-356 + .414 c 

 c = 3.502 + .046 I 



The second term of the equation shows that for each deviation 

 of one cotyledon from the mean number of cotyledons there is a 

 deviation of about four tenths of a leaf from the mean number of 

 leaves. For each deviation of one leaf from the mean number 

 there is associated a mean deviation of only about five hundredths 

 of a cotyledon. 



These lines are shown graphically with the empirical means 

 in DIAGRAM 3. The agreement between the observed and the 

 smoothed frequencies is not very close. ^ 



At present it seems undesirable to attempt a closer statistical 

 analysis of the data. Such would better be reserved until wider 

 and more precisely recorded series of observations on plants grown 

 under more closely controlled conditions are available. 



IV. Recapitulation 



The teratological race of Phaseolus vulgaris described in the 

 preceding pages has proved constant with exceptions which may 

 probably be disregarded for three offspring generations. These 

 comprise 85,371 and 7,602 individuals respectively. A limited 

 test of the fourth offspring generation has indicated perfect 

 constancy. 



The race appeared in a "pure line" of beans derived from a 

 single parent plant grown in 1907. It was isolated in seven and 

 probably in nine individuals grown in 191 2 from mass culture 

 seed harvested in 1911. All the circumstances of its origin are 

 characteristic of de Vriesian mutation. 



While Tetracotyledonous has been selected as the most convenient 

 single descriptive term, the race is differentiated from the normal 



1 A part of the discrepancy is, however, apparent rather than real. Thus the aberrant 

 means for cotyledon number for plants with 12 and 14 leaves are based upon a single 

 seedling each. Plants with 6 and 7 cotyledons are but 10 of the 1,202 individuals. 

 The very aberrant average for leaf number associated with 6 cotyledons in the less 

 mature series is based upon 3 individuals only. 



