Harris, A quantitative study of tlie factors influencing etc. 
11 
be regarded as fairly smoothing the observed means, but in NH 
there is clear evidence of non-linearity. Tbis is also, as already 
noted, especially conspicuous in the diagram. 
III. Discussion and Summary. 
Tbis paper, wbich is one of a series dealing with 
tbe pbysiology of seed production, embodies databearing 
on tbe problem of tbe factors determining tbe weigbt of 
tbe bean seed. 
Tbis first part based upon a series of weigbings of 
about 23,000 seeds drawn front five cultures of tbree dif¬ 
ferent varieties, deals solely witb tbe problem of tbe 
dependence of seed weigbt upon tbe cbaracteristics of 
tbe pod. Otber factors will be discussed later. All 
general discussion of literature and of observations is 
reserved. Tbe present summary deals only witb tbe find- 
ings as to facts in the pbase of tbe problem under con- 
sideration. 
Tbe influence of tbe characteristics of tbe pod upon 
tbe weigbt of tbe seed is easily measured in terms of tbe 
correlation between tbe two variables. Tbat between 
number of ovules per pod and weigbt is low. Indeed, 
botb positive and negative values of tbe coefficient occur, 
and tbe rate of cbange in weigbt associated witb a Va¬ 
riation of one ovule in number of ovules per pod ranges 
only from —.0071 to + .0052 grams. Thus number of ovules 
formed is practically negligible as a factor influencing 
seed weigbt. 
For tbe relatiosbip between number of seeds matured 
per pod and seed weigbt tbe results are more consistent. 
In all cases, tbe weigbt of tbe seeds decreases as tbe 
number of seeds per pod increases; but tbe correlations 
are low tbrougbout, averaging only—.096. Tbe cbange in 
absolute seed weight for an increase or decrease of one 
seed is only .0055 grams. 
P ,, n „ , seeds per pod, 
For tbe relative number of seeds,- - ----— 
ovules per pod, 
tbe correlations are even lower tban for absolute number, 
averaging only —.073. 
Tbe cbances of an ovule developing into a seed are 
correlated witb tbe position wbicb it occupies in tbe 
pod — tbe percentage of development increasing from 
tbe base towards tbe stigmatic end. In small pods, tbe 
rate of increase may be fairly regulär, but in largerpods 
it falls off towards tbe distal end, wbere tbe fecundity 
may be even lower tban in less distal regions. 
Tbe weigbt of tbe seed is also postively, but not 
bigbly, correlated witb its distance from tbe proximal 
