258 BOTANICAL GAZETTE [APRIL 
micropyle, or between the integuments. The course to the egg cell 
is through the micropyle and into the tip of the nucellus through the 
tissue derived from the tapetal cells, which stains deeply at the time 
and is probably conductive tissue. Thus it is seen that the tube 
grows just about as fast as the conductive tissue is prepared for it, 
and stops in the fall when it reaches the end of the mature conductive 
strand. The transference of the male nucleus has not been observed, 
but fertilization takes place about the middle of May, which is from 
five to seven months after pollination. 
ENDOSPERM. 
The antipodals very early disappear. The first result of fer- 
tilization is apparent in the action of the endosperm nucleus, which 
immediately begins to divide. The stage of free endosperm nuclei 
is very short, as cell walls have appeared in the twelve-nucleate 
stage. These walls first arise in the bottom of the embryo sac. 
Both endosperm and nucellus grow rapidly from this time forward. 
The endosperm early disintegrates the neighboring nucellar tissue 
except at two points, the tapetal strand of tissue leading down from 
the micropyle and bearing the fertilized egg at its lower end, and the 
pit at the chalazal end of the embryo sac which earlier held the 
antipodals. This and the deeply staining tissue surrounding it 
resist the action of the endosperm for some time, and by the growth 
of the base of the nucellus are pushed into a position on the side of 
the growing endosperm (fig. 23). This antipodal pit is finally 
absorbed. 
The nucellus keeps pace with the growing endosperm, 
layer being changed to make part of the inner seed coat. 
entiation of this layer is shown mainly by the larger size of its 
especially at the tip of the nucellus, and by the crowded cell contents 
which take up blue stains very readily. This layer is the only part 
of the nucellus that permanently resists the action of the endosperm 
and it is completed across the region of the chalaza so that it entirely 
surrounds the endosperm. Its nuclei are usually applied to the outer 
cell wall, and help doubtless in making the clear membrane whic 
surrounds the nucellus in the mature seed. It is thrown into folds 
shortly before the ripening of the seed (fig. 20). The endosperm 
its epidermal 
The differ- 
cells, 
