446 BOTANICAL GAZETTE [DECEMBER 
paper CAMPBELL (’oI) agrees with this description, except that he 
does not think that there is always in the mature sac a single cell which 
has the position of a synergid. 
That chromosome reduction takes place in the first division of 
the embryo sac nucleus was indicated by the presence of synapsis 
before this division in P. hispidula, as reported by JoHNSON before 
the Botanical Society of America at New Orleans in 1905. 
CAMPBELL (’or) thinks that the embryo sac of Peperomia is a 
primitive one, while JouNnson (?00) considers its peculiar structure 
as derived. In this paper it will be shown that the embryo sac is 
made up of the descendants of four nuclei which are apparently the 
nuclei of four megaspores, and that these nuclei have, by the loss 
of dividing walls, come to lie in the same cell. Some of the peculiar 
features of the mature sac are probably connected with this fact. 
For the sake of convenience, each of the four species will be 
described separately, after which the general considerations will be 
discussed. 
Peperomia Sintensii 
The material of this species was collected in Jamaica by Mr. 
W. R. Maxon and identified by M. Casimir DE CANDOLLE. 
The development of the flower and of the mother cell in the nucel- 
lus agrees with that described for P. pellucida by JOHNSON (’00). The 
flower consists of two stamens and a carpel in the axil of the bract. 
The ovule (fig. 28) is single and orthotropus, with a single integument 
(fig. 28, i), which makes its appearance about the time that the tape 
tum is cut off from the archesporium (jig. 2). : 
The archesporium arises in the apex of the nucellus as a Sin 
hypodermal cell (fig. 1), which is clearly distinguished from sade 
rounding cells by its larger size and more densely staining conten - 
At the micropylar end this cuts off a single parietal cell (fig. 2), am 
then, without giving rise to any other cells, forms the embry? ni 
The parietal cell divides first by an anticlinal wall and then by repeat 
divisions gives rise to a mass of tissue between the embryo sac a? 
micropyle (figs. 4, 28, t). the 
Owing to the scarcity of young material, I was unable to — i 
chromosomes in the division cutting off the tapetum, but : 
tapetum and in the nucellus there were regularly about sixteen on, 
gle 
