76 WEATHERWAX: GAMETOGENESIS IN ZEA MAys 
synergid, and its cytoplasm is much less dense. The nucleus is 
almost centrally located and is closely surrounded by most of the 
cytoplasm of the cell. It is a little larger than that of a synergid 
and always stands out distinctly; the nucleolus is large, but the 
chromatin granules are small and scattered. 
The polar nuclei resemble 
the egg nucleus but are often 
a little larger. They are 
usually surrounded by a dense 
mass of cytoplasm, which 
often makes detailed observa- 
tion difficult. They do not 
fuse until after the entrance 
of the pollen tube to the em- 
bryo sac, even though pollina- 
tion be artificially delayed 
until long after the normal 
time. 
The antipodal tissue con- 
tinues to grow until the time 
of fecundation, often consist- 
ing of fifty or more cells, some 

Fic. 2. Longitudinal section of female z 
floret, for — of orientation, X 75: /, of which may have more than 
lemma; ?, palea; e, embry m,nucellus; one nucleus. A number of 
o, outer ei ks #, inner ‘[itepankent= these have been observed in 
m, micropyle; ¢c, stylar canal; #, course of Gets 
pollen tube after reaching the ovary; s, the Process of division, and, 
rudimentary stamen. while accurate counts of the 
chromosomes have not been 
made, there is nothing in the appearance of the karyokinetic figures 
to indicate ,that there are any more than the haploid number as 
has been reported for many other plants. The theoretical signific- 
ance of this antipodal tissue in the grasses has never been fully 
investigated, and it may help some time to explain the female 
gametophyte of the angiosperms. It is probably the equivalent of 
the endosperm of gymnosperms, but in maize it is completely 
absorbed soon after fecundation ~~ never becomes a part of the 
endosperm of the mature seed. 

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