126 The Botanical Gazette. [March, 
Of the two conjugating nuclei, the one from the upper endof 
the sac is nearly always the larger. When the two nuclei 
approach each other, the centrospheres join two and two, and 
the two couples then separate so as to permit the two nuclei 
to come in contact (fig. 3). While the two nuclei are fusing, 
the attraction-spheres gradually unite and in them can be dis 
tinguished the two controsomes lying very close together (figs 
4, 5, 6). When the two nuclei have nearly fused, the 
centrosomes are in contact and are also uniting (fig. 6). The 
fusion of the two nuclei takes place by a gradual interchange 
of their contents. The chromatin does not seem to unite a 
definite chromosomes, but there appears to be a gradual it- 
termingling of the individual particles from which a new 
chromatin network is built up. The nucleoli of the two mt 
clei appear distinct even to an advanced stage of the conjl- 
gation, but later there appears but one, in most cases, in the 
definitive nucleus, showing that there has been a union of the 
material of the two nucleoli, or the formation of a new oe 
from nucleolar matter derived from the old ones (fig. 7): But 
the intermediate processes were not observed. i 
The endosperm is not very abundant when the embryo ® 
completely developed. It appears to be formed entirely from 
the definitive nucleus. The first division of this nucleus gene 
ally precedes the first division of the oospore (fig. 19): a 
nuclei continue to divide and spread out through the embryo" 
sac as it increases in size. In one case I observed four end” 
sperm cells at the time when the first division of the oospo 
was in the close daughter-skein stage (fig. 8). 
Phenomena of fertilization. 
The young pollen grain has two nuclei, a large sie whl 
r 
red with anilin-safranin. When the pollen grain falls 0” of 
stigma and germinates, its tube passes through the se 
and thence down through the tissue on the inner side of 
