206 The Botanical Gazette. [May, 
even when the pollen grains and active glands were taking a 
brilliant green, the fusing nuclei persisted in taking only the 
red, thus indicating that the fusion has no relation to a sexual 
process. ’ 
With the formation of the endosperm-nucleus the embryo- 
sac completes its preparations for fertilization. All my fig- 
ures, except fig. 3, are drawn from embryo-sacs in which the 
endosperm-nucleus is already formed. 
The mature embryo-sac. 
The mature sac is surrounded by a beautifully distinct wall 
of tapetal cells, ¢, figs. 1, 2 and 3, filled withdense protoplasm 
remarkably free from vacuoles. The egg apparatus usually 
occupies the micropylar sixth of the sac and displays that re- 
luctance to vary which characterizes structures directly con- 
cerned in reproduction. Indeed, there is such uniformity that 
one knows beforehand just where to focus his mind and mi- 
croscope to catch the elusive outlines of the svnergide and 
micropylar portions of the ovum. : 
The egg occupies from one-half to four-fifths of the entire 
diameter of the sac. It well deserves the name, odsphere, 
for it is often a perfect globe. Usually, however, the egg is 
pear-shaped, with the smaller end nearest the micropyle; but 
whatever its shape, there is almost invariably a large vacuole, 
occupying the greater part of the interior. Below the vacuole 
in a dense mass of protoplasm, is the egg-nucleus. 
The two synergidz generally fill the entire diameter of the 
sac. They are somewhat ovate in form and extend from the 
micropyle to about the middle of the ovum. Their nuclei do 
not seem to have any favorite position, for they are found, 
sometimes at one end of the cell, sometimes at the other, but 
perhaps, more frequently, near the middle. In a few speci- 
mens I found the nuclei doubled but never found more than 
two synergidz. In two or three cases the principal vacuole 
was found in the micropylar end, but its usual position is at 
the opposite extremity. Like the egg, the synergide are not 
protected by any membrane. 
is used to precede the paraffine, these globules become exX- 
tremely refractive and seem to be composed of cil. Connect- 
