1918] OTTLEY—IMPATIENS 293 
reduction division and giving rise to the 2-nucleate embryo sac 
(fig. 9). At this stage there is still something of the disintegrating 
micropylar cell to be seen, but at a slightly later stage it has entirely 
disappeared (fig. 10). The embryo sac is thus derived from two 
megaspores as in Viscum articulatum (TREUB 43) of the Archi- 
chlamydeae and in T: neue (HEATLEY 26) and several other 
monocotyledons. 
The two megaspore nuclei move to the opposite soe of the 
sac and divide (fig. 10). At this stage the sac is vacuolate and 
continues so until a late 4-nucleate stage (figs. 11-13). The 
8-nucleate stage follows rapidly upon the four. Two-, 4-, and 8- 
nucleate stages have all been found in the same ovary, the 2-nucleate 
stage being at the base of the loculus. It is very easy, in serial 
sections, to confuse an early 8-nucleate stage with a late 4- 
nucleate stage, as the sacs have the same shape and cytoplasmic 
appearance. 
In Eriocaulon septangulare (SMitH 40) the central vacuole first 
appears at the 4-nucleate stage. In J. Sultani the late 2-nucleate 
sac is vacuolate with large vacuoles between the two nuclei, but 
there is not one large central vacuole until the female gametophyte 
has been organized (figs. 1o-14, 17). In an early 4-nucleate stage 
there are several large vacuoles extending along either side of the 
row of nuclei (fig. 11). During the 4-nucleate stage the sac enlarges, 
the cytoplasm becomes more dense, and the large vacuoles decrease 
(figs. 12, 13). By the time the 8 nuclei are formed the cytoplasm 
is very dense and contains a large amount of stored food, and the 
vacuoles have become small and inconspicuous (fig. 14). Very 
soon, however, a large central vacuole appears (fig. 17). The time 
of the inception of this central vacuole varies considerably. It 
may arise while the antipodal polar is at the base of the sac, or it 
may not appear until the polars are in contact and near the egg 
(figs. 14, 17, 18). 
After the organization of the 8 nuclei the egg apparatus soon 
forms. The egg is more or less pear-shaped, with the larger end 
extending down below the synergids. The nucleus and greater 
part of the cytoplasm are in this region and the narrowed part 
extends up back of the synergids and is vacuolate. It evidently 
