The Inheritance of a Somatic Variation in Maize 33 
rate factors for cob and pericarp color 10 by the assump- 
tion that one of these factors may be modified while the 
other remains unchanged. But we should then have the 
no less difficult problem of accounting for the universal 
appearance of red cobs with F x red ears without respect 
to whether the parent grains stood on red or variegated 
cobs. 11 
Forced to its logical limit, our conception of the V fac- 
tor is that of a sort of temporary inhibitor, an inhibitor 
that sooner or later loses its power to inhibit color devel- 
opment, a power that once lost is ordinarily never re- 
gained. Of course it may be that there is present in varie- 
gated maize merely a dominant factor for self-color, S, that 
is temporarily inactive, but that sooner or later becomes 
permanently active. Even if this be true, 8 as an active 
factor and 8 as an inactive factor are certainly as distinct 
in inheritance as they are in development and therefore 
deserve to be designated separately. And since in one 
case there results self -color and in the other variegation, 
the factors may as well be called S and V as anything else. 
It is of course also conceivable that the S factor may re- 
peatedly arise de novo, though this seems very unlikely. 
Whatever our conception of the nature of the factors 
for variegation and for self-color in maize ears, these 
factors are certainly as distinct in inheritance as any two 
factors could well be. Moreover, there is abundant evi- 
dence, which can not be given here, that they are strictly 
allelomorphic, as indeed they must necessarily be if one 
arises by modification of the other — this on the assump- 
tion that the factors are definitely localized in certain 
chromosomes. Furthermore, these factors are to be re- 
garded as pattern factors. Though they must influence 
io Evidence that there are distinct factors for cob and pericarp color was 
presented in a previous paper on coupling and allelomorphism in maize. 
Ann. Rpt. Nebr. Agr. Expt. Sta., 24: 59-90. 1911. 
n This problem is discussed in another paper on the simultaneous modifi- 
cation of distinct Mendelian factors. Amer. Nat., 47 : 633-636. 1913. 
