1911] COULTER—ENDOSPERM OF ANGIOSPERMS 383 
the “primary endosperm nucleus,’’ we observe an act too miscel- 
laneous to represent anything so definite as fertilization. More- 
Over, we obtain positive evidence that in the embryo sac there is 
some condition that favors nuclear fusions, quite apart from what 
may be called sex attraction. 
(2) Cases of no triple fusion, followed by endosperm formation, 
are humerous. In some instances, there is not even polar fusion, 
each polar nucleus initiating endosperm formation independently. 
In other cases, the male nucleus may fuse with either of the polar 
nuclei, the other nucleus remaining out of the combination, but 
the result is always the same. When the male nucleus pairs only 
With the micropylar polar nucleus, one might expect an embryo, 
if the latter nucleus is really an egg, but endosperm is the result. 
The increasing number of known angiosperms which are habitually 
parthenogenetic furnish cases of endosperm formation in the 
absence of the male nucleus. Of course in such cases the endo- 
Sperm may be claimed to be parthenogenetic also. 
The cases of so-called parthenogenesis among angiosperms 
illustrate a wider variation in the antecedents of endosperm forma- 
tion than the mere absence of the male nucleus would seem to 
indicate. STRASBURGER has called attention to the fact that in 
the cytologically investigated cases of parthenogenesis there has 
been no reduction division, and that therefore the parthenogenetic 
€gg is a 2x egg, just what it is after normal fertilization. If the 
failure of reduction results in a 2x egg, it must result also in 2x 
Synergids, antipodals, and polars; in other words, the gameto- 
phyte has throughout the sporophyte number of chromosomes. 
And still, endosperm formation proceeds as before, when one would 
be justified in expecting embryo formation by sporophytic budding, 
@ phenomenon very common in the tissues adjacent to the embryo 
Sac. No one questions that the embryo is a sporophyte, whether 
it is a result of the act of fertilization or not, for it is recognized 
by its organization. It is pertinent to ask, therefore, why there 
Should be any hesitation in recognizing the endosperm as gameto- 
Phytic from its lack of organization, no matter how it originates. 
It is obvious that the constancy of endosperm lies in its structure 
and not in its origin. 
