458 BOTANICAL GAZETTE [DECEMBER 
arifolia these plates grow into evanescent walls which extend across 
the embryo sac and separate the nuclei. 
We are not justified, however, in extending the conception of four 
megaspores in an embryo sac to all angiosperms in which a row of 
megaspores is not formed, because we do not know that the division 
of the mother cell to megaspores may not be omitted and the place 
of the heterotypic division be changed. 
In the fertilization of P. Sintensii some cytoplasm appears to be 
taken into the nucleus. 
Nore.—Since the above was written, there have appeared two 
papers dealing with sixteen-nucleate embryo sacs. One is by COUL- 
TER,' in which he expands a suggestion offered by Lioyp in 1902, 
that when four megaspores are not formed the first four nuclei of 
the sac are spore nuclei so far as development is concerned, and says 
that the formation of megaspore nuclei cannot be omitted. 
In a paper on the phylogeny of the angiosperm embryo sac, ERNST’ 
describes a sixteen-nucleate embryo sac in Gunnera. Here he finds 
an egg, two synergids, six antipodals often in two groups of three, 
and seven nuclei which fuse to form the endosperm nucleus. He 
then attempts to fit the archegonial theory of PorscH to Gunnera, 
and concludes that the egg group represents an archegonium, while 
two more are represented by the six antipodals together with two 
of the nuclei which fuse to form the endosperm. He thinks that the 
other four nuclei fail to form an archegonium, and that the explana- 
tion which he gives of the embryo sac of Gunnera may apply m 
Peperomia pellucida. In the case of the embryo sac of P. Simiens™, 
which resembles very closely that of P. pellucida, it has already been 
shown that if we should apply the theory of Porsc# there would be 
four and not three archegonia. Ernst has not worked out the rela- 
tion between the nuclei in the embryo sac of Gunnera, and therefore 
it would seem premature to speculate as to the conditions there, but 
there seems to me to be no sufficient reason for thinking that the nuclel 
would represent three rather than four of the archegonia of PorscH. 
Jouns Hopkins UNIversity 
BALTIMORE 
* CouLTER, J. M., Relation of megaspores to embryo sacs in angiosperms: 
GAZETTE 45: 361-366. 1908. 
___ 2 Ernst, A., Zur’ Phylogenie des Embryosackes der Angiospermen- 
Deutsch. Bot. Gesells. 26: 419-437. pl. 7. 1908. 
Bot. 
Ber- 
