284 BOTANICAL GAZETTE [APRIL 
the other hand, division of the endosperm nucleus does not appear 
to take place in the absence of fertilization. 
Beneath the embryo sac there is a group of strongly thickened 
cells which probably function as conduction tissue. They stain 
deeply, and occasionally one of them proliferates into the embryo 
sac (fig. Ig). 
Fertilization 
Fertilization was not observed in a sufficient number of cases to 
make possible a very definite description of the process. The obser- 
vations indicate that the pollen tube entering the micropyle passes 
through one of the synergids or between them without destroying 
either. The contents of the undischarged tube shown in 7ig. 20 
could not be made out, but there can be no doubt that both of the male 
cells or their nuclei enter the embryo sac. Three or four cases similar 
to fig. 22 were seen, and once I found a sperm nucleus (which had 
then lost its cytoplasmic sheath) about half-way between the egg 
and the definitive nucleus. Pollination and fertilization are appa™ 
ently effected in the first flowers within the first day of their emergence 
from the water. The sexual nuclei in the egg fuse without delay, and 
their fusion is soon followed by that of the second sperm and the 
definitive nucleus. 
Only. one case of polyembryony was observed, the three embryos 
apparently originating from the two synergids and the egg (fig. 34): 
Endosperm 
The first division of the endosperm nucleus was not seen. 
The nuclei multiply rapidly, so that 16-32 of them are distributed 
about the periphery of the embryo sac before the first segmentation 
of the egg. They are elongated and flattened, and invariably take 
a position in the inner border of the parietal cytoplasm (7é- 23). 
When their number is about 64, tissue formation begins the 
appearance of delicate walls across the cytoplasmic layet- ee 
ani 
walls appear first in the micropylar and antipodal regions, 
somewhat later about the sides of the embryo sac. At this time the 
inner boundary of the cytoplasmic layer has no definite wall (jig: 24); 
and the general appearance is similar to that figured and descli®” 
by Lawson (11) as occurring in the gametophyte of Cryptomeri4» 
