1913] EAST—XENIA AND ENDOSPERM 219 
The other cases, where the endosperm is divided more or less 
equally into two types, remain to be explained. The hypothesis of 
independent development of the male nucleus seems improbable if 
one may judge from relevant cytological data on both animals and 
plants. The second hypothesis is very plausible. As a third pos- 
sibility, East and Haves have suggested ordinary ‘endosperm 
fertilization” with subsequent vegetative segregation similar. to that 
occurring in bud sports. This could be proved, according to them, 
if among the F, seeds of a cross between parents differing i in two > 
allelomorphic pairs, individuals should be found in which the 
parental characters were combined differently. No such cases 
have been recorded. 
The difficulty of deciding between the first and the second 
hypothesis of WEBBER lies in the fact that individuals of this kind 
are very rare, and when they have been found the investigator has 
not been able to say which particular endosperm character was 
carried by the male cell and which by the female cell. This was 
because they have occurred in selfed hybrids where both pollen 
and egg cells were segregating various Mendelian factors. In the 
experiments now to be described, this difficulty has been overcome. 
The red color in the aleurone cells of maize is due to the inter- 
action of two factors that may be represented by the letters C and 
R; this color may be changed to purple by the presence of a third 
factor P. Red is RC and purple is PRC, therefore, although it 
must be understood both that other factors which have never been 
lost in any variety may enter into the combination, and that other 
factors which have been lost in certain varieties may affect the 
development of color. 
Six homozygous white varieties may exist with the following 
zygotic formulae: PPRRcc, PPrrec, PPrrCC, ppRRec, pprrCC, and 
pprrec. Any cross between these varieties of such a nature that 
R and C or P, R, and C are brought together results in the red or 
the purple color respectively. 
Among the selfed maize ears that had been produced in the 
course of the writer’s experiments were a number giving red 
wrinkled and white wrinkled seeds in the ratio of 3:1. These 
white seeds must have either the formula ppRRcec or pprrCC. 
