The Ohio Naturalist. 
[Vol. Ill, No. 8, 
iso 
The antipodals are absorbed very early (Fig. 8), and the sac 
enlarges very rapidly, especially from the antipodal end, forming 
almost a complete circle and enclosing a mass of the basal cells of 
the nncellus in the center of the camphylotropous ovule 
Fig. 22). The first division of the endosperm occurs at about the 
same time as the first division of the embryo. After that it 
divides very rapidly, forming the typical peripheral endosperm* 
lining the embryo-sac (Fig. 16). At the antipodal end of the sac 
the endosperm is always more dense than in other parts of the 
sac (Fig. 17), and probably makes the absorption of the nncellus 
more rapid. The mieropyle and the pollen tube (Fig. 16 ) were 
very clear in many preparations, but the act of fertilization was 
not observed. However, several cases were observed which indi- 
cated that the second sperm nucleus might unite with the two 
polar nuclei, but were not sufficiently clear to draw a conclusion. 
EMBRYO. 
The fertilized egg divides by transverse walls to form three or 
four cells in an axial row (Figs. 9-12). Typically the row con- 
sists of three cells developed in acropetal order. The upper of 
these cells next divides by a longitudinal wall (Fig. 10). This is 
followed by a similar division in the next lower cell (Fig. 11). 
The two upper cells now divide by longitudinal walls at right 
angles to the first, thus forming a quadrant (Fig. 12). In the 
meantime one or more transverse walls have been formed in the 
basal cell, thus lengthening the suspensor. The embryo proper 
is now usually composed of three or four tiers of cells ( Figs. 13, 
14, 15). Each tier of cells divides first longitudinally and then 
more or less irregularly, by both transverse and longitudinal 
walls, forming an embryo almost spherical in shape, but slightly 
larger on the side away from the funiculus (Figs. 13, 14, 15, 16, 
18). The protoplasm in the upper two-thirds of the embryo is 
usually more dense than in the lower one-third (Fig. 16). 
The suspensor originates as a single cell (Figs. 9-12). This 
cell usually divides by the formation of transverse walls (Figs. 
13, 14, 16), but occasionally divides by longitudinal walls (Fig. 
15). The formation of transverse walls is followed by a longi- 
tudinal division in either one or both cells (Figs. 16, 18). After 
this it was impossible to follow the divisions. However, it 
always remains short, but becomes very much widened (Fig. 19) 
as a result of longitudinal division. By the time the embryo has 
reached three-fourths full size the suspensor has usually disap- 
peared (Fig. 20). 
The cotyledons originate from opposite points of the almost 
spherical embryo (Fig. 18, c, c). The outer of these two points 
* Ilegelraaier, Dr. Untersuehungen ueber die Morphologie der Dicotyledonen-Endo- 
sperms. Nova Acta d. K. L. C. D. Akad. d. Naturforeher 49. 1885. 
