492 WEATHERWAX: SPIKELETS OF ZEA Mays 
The peculiar details of the embryo sac of the grasses have long 
been know, as Golinski (2) shows in his review of the literature. 
In the early stages of devel- 
opment it is not unlike that 
of many other angiosperms. 
I have found in the case 
of Zea Mays no evidence 
of the disorganization of any 
of the megaspores, and it is 
probable that all four func- 
tion as in the group of plants 
of which Lilium is the class- 
ical type. 
In cytological details I 
have found nothing in con- 
flict with Guignard’s de- 
scription (3, p. 44) of the 
mature embryo sac, and only 
those details will be repeated 
in which there is some sig- 
nificant peculiarity After 
the organization of the em- 
bryo sac the antipodals di- 
vide until there are a large 
Fics. 27 and 28. Outer integument ang) number of cells—sometimes 
twenty-five or more—some 
inner integument; Oo, Ovuley If iidepeig, of which have more than one 
nucleus (PLATE 23, FIG. I). 
The polar nuclei do not fuse before the fecundation of the egg. 
The abortive stamen of the upper flower’ of the spikelet de- 
velops in the same manner as the functional one of the male spikelet 
up to the formation of the pollen mother cells; but the loculi are 
much smaller, and the pollen mother cells fewer than in the normal 
stamen. Disorganization begins in the tapetal. region, and the 
pollen mother cells are consumed before the epidermis is affected 
(Text-FIc. 30). At anthesis these stamens are small, inconspicu- 
ous, disorganized appendages near the base of the pistil (TEXT- 
FIGS, II, 31). 
