684 Campbell. — Sludies on the Araceae. 
second peculiarity is the extraordinary variation in the number 
of nuclei in the embryo-sac, and in the character of the struc- 
tures developed in it. The number of nuclei ranges from 
4 to 12, and the polarity is usually but slightly indicated. 
Multiple nuclear-fusions are of common occurrence, and it is 
often impossible to be certain which of the structures represent 
the egg- apparatus, and which the antipodal cells. 
3. In specimens of an undetermined species (Dieffenbachia 
Aglaonema Hort.), perhaps identical with A. commutation , the 
endosperm may arise from the direct division of two nuclei 
(or possibly a single one) at the base of the sac, without any 
formation of polar nuclei. 
4. A. pictum does not depart to any marked extent from 
the usual angiospermous type. The pollen-spore of this 
species has two generative nuclei. 
5. The embryo of Aglaonema , although reaching a large 
size, shows little differentiation of its external parts, and its 
tissues are almost perfectly homogeneous. In the ripe seed 
it almost completely fills the embryo-sac. The nucellus is 
relatively small, but the integuments and base of the ovule 
are very massive, and comprise the greater part of the seed. 
6. In Spathicarpa the development of the ovule and embryo- 
sac are of the usual type. After fertilization the antipodals 
become very greatly enlarged, and one of them may divide, 
so that there are often four antipodals present. The nuclei 
of the antipodal cells become enormously enlarged. 
7. The embryo of Spathicarpa remains small in the ripe 
seed. The external organs are indicated, but the tissues 
remain but slightly developed. 
8. The development of the endosperm in both Aglaonema 
and Spathicarpa proceeds gradually from the base of the sac 
until it is completely filled. It is probable that this is the 
ordinary method of endosperm-formation in the Araceae. 
