(3 Earris, A quantitative study of the factore influencing etc. 



Apparently, therefore, the pods, in which thc number of 

 seeds is above the average, produce lichter seeds than those of 

 average (or lower) fertility. But the difference is not large. The 

 inliuence of seed number is shown by the second term of the re- 

 gression equations, which are: 



These straight line equations are also represented in Diagram 1. 

 The absolute change in seed weight as one passes through a ränge 

 of one seed per pod is clearly very slight, amounting in the ex- 

 treme case to only 13/1000 th of a gram, and averaging only 

 55/ 10,000 th gram. 



These results are in agreement with those already announced 

 for Staphylea and Cladastris. 1 ) 



If the correlations between number of seeds developing per 

 pod and seed weight be negative, then one might expect those 

 for number of ovules failing to develop per pod and seed weight 

 to be positive. But since both the number of ovules and the 

 number of seeds are concerned in determining the number of ovules 

 which fail to develop, one might expect these results to be more 

 irregulär than those for number of seeds. This is, as a matter of 

 fact, the case. Three of the constants are positive and two are 

 negative. The two negative constants taken alone are the least 

 probably significant of the five. The mean value for the five 

 series is -f- -065. 



A priori, one might suppose that the dosest of all the inter- 

 dependences would be that between the relative number of seeds 

 which develop per pod and weight. The actual correlations between 



the ratio : —. — - — ' — 3 are shown in the final column of the table, 

 ovules per pod 



Three are positive, two negative. The two positive constants 

 cannot be considered significant with regard to their probable errors. 

 The largest is — .199. The average is — .073. Thus, the corre- 

 lations for relative number of seeds per pod substantiate those for 

 actual number of seeds per pod, although they are more irregulär 

 and on the average lower. 



The thing which impresses one about these constants is this: 

 there is but a very slight correlation between the fertility characters 

 of the pod and the weight of the seed which it produces. These 

 results are in direct contradiction to the kind of Statements which 

 are sometimes made by biologists. They show what caution must 



*) Harris, J.Arthur, Seed Weight in Staphylea and Cladastris. (Torreya. 

 Vol. XI. 1911. p. 165—169.) 



