1904 | OPPERMAN: LIFE HISTORY OF ASTER 357 
closely, as to their structure, with Chamberlain’s description, 
but they do not confirm the observations made by Martin (1892), 
who found only four antipodals. These four cells were never 
arranged in a single longitudinal row, and he did not figure them 
as separated by cell walls. 
Definite cells appear in the antipodal region very early in the 
development of the embryo sac. As a rule, these cells have 
reached their greatest development when the embryo sac is 
ready for fertilization, but occasionally they continue to grow 
for some time after fertilization. It often occurs in A. Novae- 
Anghae and in A. undulatus that the lowest of the antipodal cells 
becomes very much enlarged (figs. rz, 14, 16). The nuclei of 
this cell were found in a few cases to be somewhat larger than 
the nuclei of the other antipodals, but in no instance was I able 
to find in this lowest cell an antipodal oosphere as described by 
Chamberlain (1895). However, an egg, doubtless derived from 
one of the upper antipodal nuclei, was observed and will be 
described later. In one preparation an embryo sac was found in 
which the lowest antipodal exceeded in width the expanded 
upper portion of the embryo sac, but there was nothing in the 
character of its nuclei to indicate the presence of an antipodal 
&gg (fig. 16). 
There seems to be no limit to the number of antipodal nuclei 
in Aster. Cells which contained only one nucleus were found in 
only a few cases. Figs. rg and 15 illustrate two antipodal cells, 
One of which contains fourteen nuclei of various sizes and the 
other nineteen small nuclei. 
The antipodals persist until the embryo sac is in an advanced 
Stage of development, and their function is probably that of con- 
veying nutrition to the developing embryo. In several instances 
two or three cells just below the antipodals were observed to 
fetain their normal appearance, containing cytoplasm and 
nucleus (fig. 5). It may be that these cells are active in sup- 
Plying food to the developing embryo, as described by 
Ferguson (1901) in Pinus and confirmed by Coker (1902) in 
Taxodium. 
