WEATHERWAX: GAMETOGENESIS IN ZEA Mays 83 
plicate the problem. A good résumé if these is given by Coulter 
and Chamberlain (5, pp. 165-186), and more are being added 
from time to time. 
Miss Sargant (17, p. 702) stated clearly the problems involved 
in the interpretation of the triple fusion and reviewed the explana- 
tions that had been given up to 1900. Although her paper ap- 
peared very early in the investigation of the question from the 
modern point of view, it showed such a clear insight into the 
nature of the problem that the data that have accumulated since 
that time have afforded little foundation for further constructive 
work. 
Some have considered the endosperm merely a belated pro- 
thallium, the triple fusion of nuclei being non-sexual and of no 
more significance than the nuclear fusions that often occur in 
vegetative tissue. Strasburger (18, p. 308) calls the triple fusion 
a ‘‘vegetative fertilization,” as contrasted with the ‘‘generative 
fertilization” of the egg. These types of fecundation resemble 
each other in the transmission of certain hereditary characters, 
but they differ in the nature of the new individuals produced. 
Again (17, pp. 704-706), the endosperm may be looked upon as 
a monstrous embryo, its aberrant nature and limited development 
being determined by the antipodal one of the polar nuclei, inas- 
much as its chromosome number is known to be irregular in many 
plants. According to this view, the endosperm is neither sporo- 
phyte nor gametophyte, but a new generation, characteristic of 
the angiosperms alone, and for which Trelease (19) has proposed 
the name xeniophyte, because it is the generation in which xenia 
may occur. 
All agree upon the function of the endosperm as an organ of 
nourishment for the embryo, and its rapid growth has been attrib- 
uted to its sexual, or pseudo-sexual, origin. Collins and Kempton 
(2) and Jones (14) have even shown that hybrid endosperms, 
produced by crossing varieties of maize that have been selfed for 
some time, show a perceptible increase in size over those of the 
parent races. This is attributed to the increased vigor usually 
resulting from hybridization. Miss Sargant (17, pp. 709-710) has 
suggested that the introduction of the paternal elements into the 
primary endosperm nucleus may be a device of the plant to pro- 
