330 BOTANICAL GAZETTE [May 
or possibly it is the generative nucleus itself, with which it 
agrees in size and staining. Its deep blue color is in strong 
contrast to the red of the synergids -and oosphere, and of the 
tube nuclei of the microspores. 
Since no embryos are formed the contents of the embryo 
sac sooner or later disorganize, always in this order : antipodals, 
synergids, oosphere, definitive nucleus. The definitive nucleus 
persists long after the other constituents of the embryo sac 
have disappeared. In a few instances a small number of free 
endosperm nuclei were found, and in one case these had 
arranged themselves into an incomplete parietal layer, but ne 
cell formation of the endosperm was observed. Whether fertil- 
ization had been effected in these cases I could not make out, 
but the egg which was still intact had made no progress 
toward the development of an embryo. -The coincidence 
of the usual failure of the pollen tube to penetrate ta: He 
oosphere with the infrequency of a division of the definitive 
nucleus lends weight to the generally accepted view - “ 
stimulus which induces this division is the act of fertilization 
INTEGUMENTS OF THE OVULE. 
The beginnings of the integuments may be seen in fig a 
About the same time there begins a bending of the aay . 
checks the growth of the outer integument where - See a 
contact with the funiculus. By the time such a pipes 
reached as that shown in jig. 72 the ovule is comple: oss 
tropous. The integuments are each two cell layers 9 ne oe 
with the cells above the micropyle much the largest. — = re- 
portion of the outer integument next to the funiculas 8 4°8 
sented by a thin layer of empty cells. 
CYTOLOGY. 4 
have 
Only a few additional remarks need be made. ! 
tolog- 
found Ejichhornia a favorable subject for the study ouaeel 
ical phenomena. Oil cells and glandular cavities ge interferes 
and a mucilaginous secretion pervades the cells an 
