1900] LIFE HISTORY OF QUERCUS : 415 
5 The course of the pollen tube in relation to the synergids | 
"have been unable to determine. In the most positive case of a 
7 pollen tube within the embryo-sac the course seems to have 
_ been between the synergids and the wall. Many cases were 
_ found of an open micropyle strewn with mucilaginous residue, 
a indicating that the tube had passed, but a most careful search 
failed to reveal its presence within the sac. It is not unusual to 
find in the micropylar region of the sac numerous refractive 
the oosphere was not observed. 
ENDOSPERM. 
There is a very early and copious development of endosperm. 
Thave no proof that this begins before the fusion of the male 
cell with the oosphere, yet its universally prompt appearance 
when the sac reaches maturity seems to me to indicate a doubt- 
ful time relation. This early appearance of endosperm is a 
Source of perplexity in the investigation of male cells and anti- 
“Podals. The nuclei of the endosperm lie free in the stratum of 
‘Protoplasm about the wall of the embryo-sac, and the cells show 
MO evidence of running in walls up*to the time at which the 
Mbryo cuts off cells to form the dermatogen. fig. 36 shows 
the condition of the endosperm as it occurs in connection with 
the embryo illustrated in ig. 39.- 
EMBRYO. 
' Cells to form the dermatogen, the vertical division occurs 
p= 37-39). | 
