STUDIES OF THE DEVELOPMENT OF PEPEROMIA HISPIDULA 393 
the endosperm until the starch of the perisperm is exhausted. This 
restriction of the functions of the endosperm to that of nurse for the 
embryo, is the next to the last step in the disappearance of the endo- 
sperm, which has become practically complete in the Orchidaceae, 
the Podostemaceae and the Helobiales. 
7. The i6-nucleate embryo sac of Peperomia like those of other 
atypical angiosperms cannot be regarded as primitive. In the first place 
it is highly peculiar in being the product of four megaspores, germinating 
in a single protoplast, a phenomenon unknown among simpler forms. 
In the second place the angiosperms with i6-nucleate embryo sacs 
belong to isolated genera, in many unrelated families whose other 
genera have 8-nucleate sacs, from which it is believed the i6-nucleate 
sacs have become specialized independently in each family. Thirdly: 
the whole vegetative and reproductive structure and development of 
this species favor the view that it is a specialized form among its allies. 
The Harpswell Laboratory, 
August, 1914. 
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