126 BOTANICAL GAZETTE [avoust 
Comparing the two methods of obtaining the independent corre- 
lation between number of seeds and length we have: 
Correlation of index and length................-.. 0.29060 .0113 
Partial correlation coeflicient..<... 00... es o.3128+0.0111 
PO eee ee ee ee 0.0222 
This difference is certainly of no practical importance. 
Summary 
1. In considering the influence of the number of seeds develop- — 
ing upon the dimensions attained by the fruit, the number of ovules 
formed cannot be disregarded, since a correlation attributed directly 
se i ae ons? 
ere 
to the influence of the development of the seeds may be in partat least q 
due to an interdependence between the number of ovules formed and q 
the dimensions of the fruit. The influence of the number of ovules 
can be neglected only when the coefficient of correlation betweet 
number of ovules and size of fruit is demonstrated to be zero. This 
point is well illustrated by a series of 3,000 pods of Cercis, where the 
correlations for ovules and length is 7,,=0.428+0.010; while the 
correlation for seeds per pod and length is only 74 =0. 5060£0-09 
2. Two methods for freeing the correlation between the number 
of seeds developing and the length of the fruit from the influence of 
the relationship between the number of ovules formed and the length 
of the pod are suggested; the first is the determination of the parti 
correlation coefficient, that is, the correlation between number of 
seeds and length for constant values of numbers of ovules pet pod; 
the second is the determination of the correlation between the index 
Seeds devcloring bet Pod and the length of the pod. 
The results from the data in hand are in close agreement, 
Ps] =0 .3130.011 
r1=0.291+0.011 
Psi — Tj) =0 .022 
and we conclude that of the gross correlation of about p=9°-5° inf 
number of seeds and length of pod a considerable portion, S4Y use 
0. 300 roughly, is due to some morphogenetic or physiological relation” 
ship between the number of seeds developing and the length a 
pod. 
Bia ee a apna e Fe iy 
aia ee bs WS Se see eee 
Goce 
a 
MES 
