WEATHERWAX: GAMETOGENESIS IN ZEA MAys 85 
_ The maize endosperm is either sweet or starchy. The starchy 
tissue occurs in two forms, one corneous and translucent, and the 
other soft and white; and different proportions and variations in 
the arrangement of the soft and corneous portions gives rise to 
dent, flint, pop, and soft types. The mature seeds of the sweet 
varieties are always wrinkled; they are to be understood as having 
pop, dent, flint, and soft potentialities remaining invisible because 
of limited starch development. The starchy condition is dominant 
to the non-starchy, but dominance among the variations of the 
starchy condition is a less definite thing. 
The corneous endosperm is either white or yellow; the yellow 
color, which has been found to be due to more than one hereditary 
factor, is dominant. It may appear in either the starchy or the 
sweet endosperm. 
The aleurone is red, purple, or colorless. Two hereditary 
factors are necessary for the production of the red color, and these, 
interacting with a third, produce purple. The presence of either 
color combination is dominant to its absence, but other color genes 
are also present, at least one of which is an inhibiting factor. 
Correns found (4) in certain crosses that a white variety pol- 
lenized with pollen from a purple did not always produce purple 
aleurone, although the embryos of the same seeds proved to be 
hybrids. He explained this non-appearance of xenia by assuming 
that the recessive factors carried by the two maternal nuclei 
entering into the primary endosperm nucleus were dominant over 
the one factor introduced by the sperm, although the latter was 
ordinarily dominant. 
East and Hayes (7, pp. 58-59), having found a better explana- 
tion of this aberrant result, attacked Correns’s hypothesis on the 
ground that quality and not quantity of chromatin is the deter- 
mining factor. In this argument they failed to distinguish between 
the idea of double quantity and quality acting twice. 
In later experiments (12, p. 12) they found that when reciprocal 
crosses were made between a soft and a corneous variety, the 
quality of the endosperm produced was always determined by 
the female parent. At the same time it was shown that a soft 
white female crossed with a flinty yellow male produced soft yellow 
seeds. The appearance of xenia in color showed that the peculiar 
