374 
DUNCAN S. JOHNSON 
the nucleoli differ greatly in size, some having ten times the diameter 
of others (figs. 103, 104, 105). 
The spindles for the second mitosis in the endosperm are usually 
nearly longitudinal, and the walls formed are somewhat transverse to 
the ovule (fig. 104). The formation of the cell wall between the 
nuclei, in this as in the first and in all later divisions in the endosperm, 
follows immediately on nuclear division. The four endosperm cells 
resulting from the second division usually divide next by spindles 
perpendicular to those of that division, and hence by walls longitudinal 
to the ovule. Later a number of more or less transverse walls appear 
and there is thus formed an endosperm which, in the ripe seed, con- 
sists of about 40 or more cells arranged somewhat regularly in 3 or 4 
tiers (fig. 108). The numbers just given are for the endosperm and 
embryo shown in figure 108, which is the largest found among scores 
of the ripest attached or fallen seeds collected by the writer. In figure 
no are shown the endosperm and embryo from a seed that was 10 or 
12 days in damp moss after being collected, before being dropped into 
formalin and then sectioned. The embryo is farther developed than 
the one in figure 108, and the endosperm shows 27 cells in the single 
section. It seems probable that the difference in stage of development 
of these two seeds should be counted as due to the beginning of germi- 
nation in the latter, though it is possible that development may some- 
times go this far before the fruit falls from the plant. In the ripe seed 
these endosperm cells have irregular nuclei of 10 to 20 /x in diameter, 
with numerous nucleoli, and have rather densely staining protoplasts. 
Scattered through the cytoplasm of the endosperm, from the one- 
celled stage onward, are found quite numerous rounded bodies of the 
size of the nucleoli, which, like those of the mature embryo-sac, are 
colored black by Flemming's fixing fluid. This fact, together with 
their appearance, and their continuity from the mature sac onward, 
indicates that they are of the same sort of oil or fat that was demon- 
strated in the sac. These globules seem to diminish in size as the 
endosperm cells multiply. In the mature endosperm of this species, 
as in P. pellucida, stored starch, so far as the iodine test shows, is en- 
tirely wanting. 
The embryo. — From the time the 14 contributing nuclei are grouped 
for the formation of the primary endosperm nucleus until their fusion 
is completed, two nucleoli are found in the single nucleus of the egg. 
No cases were found where the distinct male and female nuclei could 
