674 Campbell. — Studies 071 the Araceae. 
embryo-sac, are worthy of note, as is also the absence of 
marked polarity in the arrangement of the nuclei. The 
frequent occurrence of multiple nuclear fusions is also inter- 
esting, as in this respect this species furnishes a condition 
intermediate between that found in Peperomia and that occur- 
ring in the typical Angiosperms. A similar condition has been 
found to exist also in the peculiar genus Gunner a 1 . 
Where the egg-cell was evident it was usually hemispherical, 
and was either at the apex of the sac or, more often, laterally 
placed. While the pollen-tube was seen in a few cases, 
the fertilization was not satisfactorily made out, and it is 
possible that some of the apparently abnormal appearances 
encountered may have been due to lack of fertilization. 
The development of the embryo is slow at first, and it 
remains very small until the endosperm is well advanced 
in its development. It is not rare to find the embryo-sac 
filled with a solid mass of endosperm, without any certain 
evidence of an embryo being present at all. 
The Endosperm. 
It is not probable that the formation of the endosperm 
is entirely uniform in Aglaonema coinmutatum. To judge 
from the frequency with which multiple fusions of the nuclei 
of the embryo-sac are encountered, it is likely that in such 
cases the primary endosperm-nucleus results from such fusions, 
although it also probably may arise from the fusion of two 
nuclei, as in most Angiosperms. The definitive endosperm 
nucleus was not seen, nor was it possible to find the first 
division : but to judge from a comparison with Spdthicarpa 
and Anthiirium , in which the young endosperm presents 
much the same appearance, it is probable that the first 
division is accompanied by a wall which cuts off a relatively 
small cell from the base of the embryo-sac. This is followed 
by a similar division in the cavity of the embryo-sac, and 
1 Schnegg, Beitrage zur Kenntniss der Gattung Gunnera, Flora, Bd. 90, 
pp. 161-208 (1902). 
