262 BOTANICAL GAZETTE [APRIL 
cut off by the partition wall (fig.77). Just what the function 
of these lower endosperm cells may be the writer is not pre- 
pared to state. In the earlier stages the whole compartment 
has a glandular appearance, much like the vesicular cell of the 
suspensor. It seems possible, therefore, that it may play an 
important part in the transfer of food material from the funi- 
cular region, beyond the antipodals, to the cotyledon, and 
especially in facilitating the formation of the cap of endosperm 
which covers the tip of the cotyledon. 
DEVELOPMENT OF THE EMBRYO. 
After fertilization the large spherical nucleus of the oospore 
lies in about the same position as that occupied by the oosphere 
nucleus before fusion (fig. 32). The oospore now begins to 
push downward into the sac and is surrounded by a definite cell 
wall, and usually one or more large vacuoles appear above it 
( figs. 33,35). The formation of vacuoles in the rear of moving 
nuclei seems to be of quite general occurrence, especially in the 
embryo sac. The nuclei seem to be carried along by the 
streaming of the cytoplasm, which as it advances develops a 
vacuole behind it. 
€ first division of the oospore is transverse (figs. 36, 3 8, 
39). After this the lower cell elongates and divides again by a 
transverse wall, making the first three cells of the pro-embryo, 
which are thus produced in acropetal succession (fig. g6). The 
upper cell never divides, and forms the vesicular suspensor cell, 
which immediately begins to increase enormously in size. The 
lowest cell gives rise to the terminal cotyledon, and its ge 
| division, which may occur immediately (fig. 47) or may 
_ delayed for a considerable length of time, is always eee. 
dinal. _ The middle cell gives rise to the apex of the stem, the 
hypocotyl, the root tip, and all the suspensor cells except the 
vesicular Pa its” ae sions Leaps in basipetal succession. 
ae ourse : fore, is the same as that given 
| Plantago, except in cer- 
ee elated poe IES cas 
SPOTS RES CU EtE Ds: Heap REMI OCToe Nato ees Ag. a ee maa 
: s which will be mentioned later, and 
| 
aaa 
Bae en ees 
Sh has. = hoe 
Pee Ose 
