780 THE AMERICAN NATURALIST. [VoL. XXXVI. 
Treub describes a large number of sporogenous cells in Casua- 
rina, several developing into complete embryo sacs. The multi- 
cellular archesporium in this case is comparable to that of the 
pteridophytes and gymnosperms. This increase in the number 
of sporogenous cells is seen in a lesser degree in Arvisema tri- 
phyllum (Fig. 2). In the latter the original hypodermal arche- 
sporial cell divides longitudinally into 2—4 (occasionally more). 
One of these, as a rule, becomes at once the embryo sac, but 
sometimes there are first transverse divisions. It is possible 
that there may sometimes be more than one primary arche- 
sporial cell in Arisaema, z.e., the whole sporogenous tissue may 
not certainly be referable to the division of a single hypodermal 
cell. This point, however, needs further investigation. 
CASUARINA. 
The very peculiar genus Casuarina, according to Treub's 
investigations,! differs decidedly from the other angiosperms, 
not only in the large development of the sporogenous tissue of 
the ovule, but also in the structure of the developed embryo 
sac. This has no antipodal cells, and all the cells of the egg 
apparatus, which are variable in number, are formed from the 
division of a primary cell. The egg, moreover, is surrounded 
by a cellulose membrane before fertilization takes place, a con- 
dition unknown among other angiosperms. Before the egg 
cell divides (and Treub believes before it is fertilized) there is 
a rapid increase in the number of endosperm nuclei. A demon- 
stration of the actual fertilization was not made, and this point 
must remain for the present in doubt. Should it be verified, it 
might well be compared with the condition existing in Peperomia. 
PEPEROMIA. 
In the genus Peperomia the writer? found that there is 
normally a doubling of the nuclei of the embryo sac before 
fertilization ; Ze. instead of the eight nuclei usually found in 
the mature embryo sac, there are sixteen (Fig. 3). This fact 
1 Le cit. 
2 Campbell. The Embryo Sac of Peperomia, Annals of Botany, vol xv 
(March, 1901), pp. 103-118. 
