222 BOTANICAL GAZETTE [SEPTEMBER 
formation originating with the germination of the megaspore, 
although fertilization occurs during the process. From the time 
of HormetsteR the morphological character of the endosperm of 
angiosperms was considered to be the same as that of the gymno- 
sperms until the double fertilization was discovered. This fact 
gave rise to the idea that the angiosperm endosperm might be 
a sporophytic rather than a gametophytic structure, its nature 
being that of a monstrous embryo, or possibly that it is a composite 
tissue neither gametophytic nor sporophytic. 
Most botanists, however, have held with SrRASBURGER to the 
original idea that the endosperm is gametophytic. STRASBURGER 
concluded that the second fusion is not a true act of fertilization 
uniting the parental qualities and forming an embryo, but a vege- 
tative fusion acting merely as a stimulus to growth. Miss SARGENT, 
however, believes that it is a degenerate embryo, the monstrous 
character being caused by the interference of the antipodal nucleus 
having a vegetative character and an indefinite and usually redun- 
dant number of chromosomes in the act. 
The difficulty in the situation appears to be the obscurity of the 
phylogenetic history of the fusion of the two nuclei in the embryo 
sac and the subsequent fusion with the second male nucleus. The 
problem is further complicated by the irregularity of endosperm 
formation in various species. Although triple fusion appears to 
occur in the majority of angiosperms, the following important 
general variations have been noted. In addition to these general 
variations many minor deviations have been found (COULTER and 
CHAMBERLAIN 4). («) Vegetative endosperm formation may take 
place in a similar manner to that occurring in gymnosperms. This 
may occur without fertilization, or before or after fertilization. 
Usually the endosperm tissue is formed from the descendants of 
the antipodal cells, but the chalazal nucleus may degenerate and 
the endosperm be formed from the micropylar polar nucleus. 
(2) The polar nuclei may not fuse, but divide independently. 
(3) Fusion may include many cells. 
roiceerainiy — formation may be initiated by a 
albNtnes ahs poe mt ang may be divided into two parts by a ce 
vision. Even when the latter phenomenon 
