240 



MEMOIRS OF THE NEW YORK BOTANICAL GARDEN 



fact is greater than the mode by ahnost one unit — whereas in the 

 cotyledons the a\'erage was less than the modal class. 

 The variation constants are as follows: 



Mean Standard deviation 



Less mature series 4.991 ± .065 ; 1. 991 ± .046 



More mature series 4.852 db .047 1.933 ± .033 



Difference .139 ± .080 .058 ± .057 



More and less mature combined 4.902 ± .038 1 1.955 ± -027 



Coefficient of 

 variation 



39.89 ± 1.05 



39.84 ± 0.79 



.05 ± 1. 31 



39.88 ± 0.63 



The samples do not differ significantly in any constant. 

 Comparing the constants for number of cotyledons and leaves 

 on the basis of the total materials I find the following constants: 



Constants for cotyledons! Constants for leaves Difference in constants 



I I 



Mean 3-730 ± .013 i 4.902 ± .038 1.172 ± .040 



S.D 654 ± .090 j 1.955 ± -027 1 1.301 =h .094 



C.V , 17.54 ± 0-25 I 39-88 ± 0.63 I 22.34 ± 0-68 



Thus the mean number of leaves is about 31.4 per cent higher 

 than the mean number of cotyledons, the al^solute variation in 

 leaf number is about 200 per cent greater and the relative" varia- 

 tion as measured by the coefficient of variation is over twice as 

 great as in the case of cotyledon number. 



The number of leaves per plant is in some degree related to 

 t he c haracte r of the axis. Examined in the crudest manner 

 possible,^ T)ydetermining the average number of leaves produced 

 by plants witii different types of axis, I find the following results: 



Thus an increase in the number of primordial leaves is associ- 

 ated with a broadening or division of the axis. This increase is 

 distinctly greater than in the case of the cotyledons. 



' With a more careful classification of the .structure of the axis it will be profitable to 

 apply correlation formulae to the i)roblcm. 



