The Inheritance of Quantitative Character* in Maize 107 
ing as the early parent but none of which were quite so late as 
the late-flowering parent. In general the same relative order was 
maintained in ripening as in flowering. Eoughly the number of 
days from planting to flowering was 00 per cent of the number of 
days from planting to ripening. The relative lengths of the two 
periods may, however, depend somewhat upon the season at which 
the type in question matures. 
In general, then, it may be said that the results secured in 
the experiments with maize were what might well be expected if 
quantitative differences were due to numerous factors inherited 
in a strictly Mendelian manner. It is quite likely, as pointed out 
repeatedly in the detailed discussion of results, that genetic 
correlations occur between factors for distinct quantitative char- 
acters. These and the physiological correlations so frequently 
noted make the results more difficult of interpretation, but do 
not throw them out of the realm of Mendelian phenomena. 
Physiological correlation is a phenomenon of development, not 
of inheritance, and, as such, has less interest for students of 
genetics than for experimental morphologists. Even in practical 
plant breeding, correlations of this sort are of importance mainly 
on account of the physiological or morphological limits that they 
set to the perfect development of particular combinations of 
characters. 
Real genetic correlations in the sense of gametic associations, 
are not antagonistic to the Mendelian doctrine. True, the funda 
mental principle of Mendel ism is segregation of separate factors 
and it might, therefore, be held with some degree of plausibility 
that gametic coupling of factors is non-Mendelian. But where 
the associated factors segregate regularly from other factors 
or other groups of factors, they can certainly be said to Mendelize 
— they merely Mendalize together. Such correlations as these 
have distinct importance in genetics. 
Numerous apparent correlations, genetic as well as physio- 
logical, have been encountered in these experiments and manv 
of them have been noted incidentally in the detailed discussions 
of results. We have reason to believe, for instance, that length 
of ear is directly correlated with height of plant and inversely 
correlated with number of rows per ear. Xumber of rows seems 
also to be related in some way to the character of the endo- 
sperm, since in some crosses segregates with a large number of 
rows have dent grains while those with few rows have flinty 
grains. It is apparent also that, while height of plant and 
number of stalks per plant may not be directly related, number 
of stalks and diameter of stalks are negatively correlated. Our 
records indicate that there is little if any correlation, either 
