1903 | EMBRYO SAC OF CASUARINA EIE 
most cases suggests a post-fertilization stage. The rounded form 
of his figures of eggs also suggests the same. 
Unfortunately, the material at hand showed no embryos nor 
endosperm, the oldest showing that the pollen tubes had reached 
the sac. It would have been quite interesting to note the con- 
dition of the egg during endosperm development. But if one 
supposes that Treub mistook a fertilized egg for an unfertilized 
one—a thing which might even be possible with the technique 
of today, to say nothing of twelve years ago—and if he further 
mistook a discharged pollen tube for an undischarged one, the 
formation of endosperm before fertilization would be eliminated 
from his own account. It will be recalled here that he himself 
could not be certain about seeing nuclei in the pollen tube 
except in a few cases, and in no case is more than one sug- 
gested. From the size of the tube nucleus (fg. 20, ¢) one is 
led to conclude that he saw it rather than a sperm. 
A summary of my results with C. séricta, as compared with 
Treub’s with C. Rumphiana, C. glauca, and C. suberosa, may be 
Stated as follows: 
There is agreement as to the bilocular ovary, the presence of 
two ovules in an ovary and both in the same loculus, the pres- 
€nce of two integuments and a micropyle, the upright ovules 
that arise laterally from the central placenta, the multicellular 
archesporium consisting of a hypodermal plate of cells, the mas- 
Sive sporogenous tissue, the division of each spore mother-cell 
to form four megaspores, the numerous mature sacs in an ovule, 
the long antipodal prolongations of the sacs, the fertilization of 
only one embryo sac in every ovary, and chalazogamy. 
There is disagreement as to the origin of the sporogenous 
tissue, in C. stricta all of it arising from the hypodermal arche- 
sporial plate, while Treub believes that some sporogenous tissue 
near the chalaza does not arise from this plate; as to the resorp- 
tion of sporogenous cells, which Treub claims, but I was not 
able to observe; as to the sequence in the formation of the 
embryo-sac structures, which differs in no way in C. stricta from 
the Sequence usual among angiosperms; as to the character of 
the €gg-apparatus, which differs in no way in C. stricta from that 
