The Ohio Naturalist. 
[Vol. IV, No. 8, 
1 70 
compartments (Fig. 24). It seems that all three of the daughter 
nuclei continue to divdde until the whole .sac is filled with endo- 
sperm extending far down into the space formed by the di.ssolu- 
tion of the tissue of the ovule below the ba.se of the embryo-sac 
(Fig. 27). The development of the endosperm, after the three- 
celled stage, begins at the upper end, but there is no large vesicu- 
lar cell developed at the lower end of the sac, as Cook reported 
for Castalia odorata. At first the endosperm cells are quite 
large, but as the division continues the cells become much smaller, 
walls continue to be formed between the dividing nuclei until the 
endosperm is fully developed, no free cell formation taking place, 
so far as observed, at any stage of the proce.ss. 
The historj’ of the embryo as followed is the same as reported 
by Lyon. After fertilization, the oospore continues to occupy 
the same position as the oosphere and it enlarges .somewhat before 
it divides (Fig. 13). Although no two-celled embrj’o was ob- 
served, it is evident that the first division of the oospore is by the 
formation of a transverse wall. Then b}’ the formation of a 
longitudinal wall in each of the two cells, a quadrant is formed 
(Fig. 23). Although this is the typical course of development, 
very frequently the divisions are different. The lower cell often 
divides by a transverse wall, thus forming a tier of three cells in 
the proembr5’o (Fig. 22). B}' the formation of longitudinal walls 
in the quadrant, the embryo pas.ses into the octant stage. In 
ca.se of a more irregular development, the three cells of the 
embryo arranged in a row, divided by longitudinal walls, making 
a six-celled embrj’o (Fig. 25). Whether the early development 
is t3’pical or irregular, a series of divisions follows Iw which a 
spherical embryo of several hundred cells is formed (Figs. 26-29. ) 
No suspensor cell is present; so the 3'oung embryo lies against 
the nucellus at the micropjdar end and is almost surrounded b}’ 
endo.sperm tissue (Fig. 27). When the spherical embr^-o has 
reached its maximum growth, it becomes flattened at the outer 
end 1)3' the development of a collar-like ridge extending about 
two-thirds of the wa3’ around (Figs. 30, 31 and 32). This is 
followed by the outgrowth of a small protuberance from the flat- 
tened .side about parallel with the apex of the ovule. After the 
formation of the crescent-.shaped ridge, the development continues 
at the opposite side, giving rise to the two “ cot3’ledonar3' ” lobes 
of the embryo (Fig. 33). The two lobes grow downward veiw 
rapidl3’ outside the endosperm, the tissue of the ovule raj)idlv 
disappearing before them. In the meanwhile, the endosperm has 
formed a sac-like mass of tissue around the embr3-o and extends 
down into the cavit3' of the embr3’o-sac to the di.sorganizing tissue 
below. In the meantime the growth of the plumule has been 
very slow, being a dome-shaped projection of tissue occup3'ing a 
central position between the lobes but to one side of the axis of 
