452 BOTANICAL GAZETTE [DECEMBER 
The further development resembles very closely that of P. Sin- 
tensit. ‘The mature sac contains sixteen nuclei. There is one egg 
and one nucleus with the position of a synergid. Six peripheral 
nuclei are cut off against the wall of the sac. The remaining eight 
fuse to form the endosperm nucleus about the time that fertilization 
takes place. In the fusion of male and female nuclei there was seen 
no sign of protoplasm being taken into the nucleus, as described for 
P. Sintensii. Many of the stages of this species resemble P. Sin- 
tensit so closely that one might readily be mistaken for the other. 
Peperomia pellucida 
The development of the embryo sac nucleus and the structure of the 
mature sac, as described by JoHNSON, agree with the description just 
given for P. Sintensii. Therefore only the first two divisions of the 
embryo sac nucleus need be considered here. 
The first division is heterotypic and shows about ten or twelve 
chromosomes. A meshwork contracts and goes into synapsis. This 
stage is followed by an apparently continuous spirem, which divides 
into twisted heterotypic chromosomes. 
In both divisions plates are formed on the spindles. These plates 
probably do not develop further, as no larger plates or walls were seem, 
although a great number of nuclei were examined at stages which 
should show them if present. These plates probably are the reat 
nants of walls such as have been described for the other three specie 
Discussion 
As has been said, CAMPBELL (’or) considers the unusual structure 
of the embryo sac of Peperomia as primitive, and expresses the belief 
“that the contents of the embryo sac with the sixteen nuclei represent 
a prothallial tissue and the nuclei are at first entirely similar.” Jom 
SON (02), after a study of Peperomia and allied genera, comes t? the 
conclusion that the peculiarities of the embryo sac have been secon’ 
arily acquired from the ordinary angiosperm embryo sac. ae 
The present investigation seems to support the latter view. * ~ 
nuclei of the mature sac of P. Sintensii, instead of being § di 
first, bear a definite relation to each other. The presence - : 
reducing division in the primary embryo sac nucleus and the forme 
