4i8 
AMERICAN JOURNAL OF BOTANY 
[Vol. 8 
Among the resulting seeds, which were colored and starchy as expected, 
occurred two with aberrant endosperm, one of which was part colored and 
part colorless but starchy throughout and the other one part starchy and 
part sugary but colored throughout. As in the case reported by East, no 
color could have developed if the second sperm nucleus had not fused 
with a polar nucleus. Furthermore, if the second sperm nucleus had united 
with one polar nucleus (Webber's second hypothesis), the part of the endo- 
sperm so formed must have been both colored and starchy while the remain- 
ing part of the endosperm formed from the other polar nucleus alone must 
have been both colorless and sugary. The observed facts, namely, that 
the starchy-sugary seed was colored throughout and that the colored- 
colorless one was starchy throughout, indicated clearly that normal fusion 
of the second sperm nucleus with the polar nuclei had taken place. 
It remains to forestall the justifiable criticism that one or other of 
Webber's hypotheses might still account for most examples of anomalous 
endosperm, the two seeds noted above being minor exceptions, just as 
either of these hypotheses might well be used to explain the 55 aberrant 
seeds with colorless spots waxy recorded in table i , the 3 seeds with colorless 
spots corneous likewise being exceptions. In the writer's 1918 paper 
(tables 8 and 10) were recorded 33 examples of anomalous seeds with part 
colored and part colorless aleurone from crosses between types with wholly 
colorless aleurone but carrying complementary aleurone-color factors. 
These, added to the six cases reported by East (191 3), a total of 39, are 
believed to suffice as a demonstration that division of the second sperm 
nucleus independently of the fused polar nuclei is quite untenable. More- 
over, two of the 33 anomalous seeds afforded definite evidence against the 
hypothesis that one polar nucleus might fuse with the second sperm nucleus 
and the other polar nucleus divide independently, making a total of four 
such instances. These two seeds resulted from a cross of a type with 
colorless sugary endosperm and colorless aleurone carrying R with pollen 
of a type with yellow starchy endosperm and colorless aleurone carrying C. 
The aberrant seeds were starchy and yellow throughout but their aleurone 
was about half colorless and half purple. 
Since the publication of the writer's 191 8 paper, a sufficient mass of 
evidence has been obtained to remove, it is thought, any possibility of 
explaining anomalous endosperm development on the basis of a failure of 
normal fusion of the second sperm nucleus and the polar nuclei. This 
additional evidence is presented in tables 2 and 3. 
In table 2 is recorded all the available material in which corneous and 
waxy endosperm, Wx wx, are involved together with the aleurone-factor 
pairs A a, R r, and Pr pr: The male parents of all the crosses here recorded 
had homozygous corneous endosperm and homozygous purple aleurone, 
A C R Pr Wx, while the female parents of all had waxy endosperm, wx. 
In addition, the female parents of all crosses recorded in groups i and 2 of 
