1913] EAST—XENIA AND ENDOSPERM 223 
occurs, endosperm tissue may be formed in both chambers, although 
usually division proceeds only in the micropylar chamber. 
These general cytological data being given, how do the facts 
from pedigree cultures bear upon the problem ? 
Just how much weight should be given to data from only one 
species when discussing the morphological significance of the endo- 
sperm is questionable. But in maize it is evident that Srras- 
BURGER’S distinction between vegetative and generative fertiliza- 
tion will not hold. Cytological work on other species does not bear 
out Miss SARGENT’s conception, since endosperms form quite 
regularly without the interference of the antipodal vegetative (?) 
nucleus. If the perfectly regular manner in which the above- 
mentioned endosperm characters of maize are transmitted is con- 
sidered apart from other facts, there appears to be no escape from 
the conclusion that the endosperm is sporophytic in character. 
But there is another way of looking at the matter that makes the 
view of CoULTER seem more probable. 
CouLTER (3) has concluded that conditions in the embryo sac 
favor fusions of any number or kind of free nuclei—an indefinite 
process without a necessary phylogeny that results in a growth 
which is practically gametophytic. It is not dependent upon a 
male nucleus, a polar nucleus, or even a reduction division. 
The experimental evidence accords perfectly with this view. 
The superficial endosperm characters are indeed transmitted regu- 
larly when a male nucleus takes part in the fusion, but there is no 
reason for believing that the remaining maternal nuclei carry all 
the characters borne by the egg because these characters are the 
same in the nuclei concerned. The egg must usually have an 
organization somewhat different from that of the other maternal 
nuclei; although it is recognized that other nuclei sometimes func- 
tion as eggs. It is likely that a differentiation has ensued which 
makes a particular nucleus an egg, and that it is not wholly a matter 
of position. The general belief in the vegetative character of the 
antipodal cells of the embryo sac is an admission that they have 
hot received all the properties retained by other four cells. It is 
not very heretical, therefore, to assume that the cell that becomes 
the egg is different from its associates. Botanists hesitate to assume 
