FISHER: SEED DEVELOPMENT IN PEPEROMIA 233 
development of the embryo sac, that the genus is primitive, we 
are inclined to accept the view first advanced by Johnson (30) 
and since confirmed by other workers (Brown, 4; Samuels, 590) 
that the peculiarities in origin and development of the embryo sac 
of Peperomia have been secondarily acquired. 
SUMMARY 
The primary archesporial cell is single and subepidermal in all 
species of Peperomia examined. 
The nucleus of the definitive archesporial cell, or embryo sac 
mother-cell, goes into synapsis before its first division. 
Evanescent cell-walls occur following the first and second nu- 
clear divisions in the embryo sac in all six of the species of which 
the material was most nearly complete. 
The mature sac contains sixteen nuclei, one of which functions 
as the egg nucleus, one as that of the single synergid, from six to 
nine others fuse to form the endosperm nucleus, and the remainder 
are individually cut off by cell-walls about the periphery of the 
sac and afterwards degenerate. 
The endosperm is cellular from the start. 
The embryo is undifferentiated externally except for a slight 
flattening on the micropylar side. 
In Piper tuberculatum we have a typical eight-nucleate embryo 
sac, developed directly from the definitive archesporial cell, no 
degenerating megaspores being formed. 
That the first four nuclei in the embryo sac of Peperomia are 
homologous with megaspore nuclei, seems extremely probable 
from the following facts: (1) they arise from a cell which with very 
little doubt may be considered a megaspore mother-cell; (2) they 
are arranged tetrahedrally; (3) the tetrad is complete in number; 
(4) the larger than usual number of nuclei in the mature sac is in 
harmony with this view: (5) the reduction of chromosomes occurs 
in the divisions which give rise to these’four nuclei; (6) a resting 
Stage follows the formation of these four nuclei; and (7) evanescent 
cell-walls frequently follow the first and second divisions in the 
embryo sac, but not the third. 
In view of the following considerations: (1) that the primary 
archesporial cell of Peperomia is single—a condition probably 
