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METHODS IN PLANT HISTOLOGY 
in the “ resting condition” is not correct, and probably the chromo¬ 
somes of the two gametes never fuse. 
The Endosperm.—Some of the preparations intended for fertili¬ 
zation will be likely to show early stages in the development of 
endosperm. 
Fig. 112 .—Plumbagella micrantha: longitudinal section of ovule showing the embryo sac, 
with the egg and endosperm nucleus ready for fertilization. Stained in iron-alum haematoxylin. 
Eastman Commercial Ortho film, Wratten E filter (orange); Bausch and Lomb 8-mm. objective 
N.A. .50; Spencer ocular X6; arc light; exposure, 1 second. Preparation by Dr. K. von O. Dahl- 
gren and negative by Dr. P. J. Sedgwick. X208. 
In rather long, narrow embryo sacs, a cell wall is likely to follow 
even the first division of the endosperm nucleus, so that the endo¬ 
sperm is cellular from the beginning. Ceratophyllum, Monotropa, 
and Verbena will furnish material of this type. 
In large, broad embryo sacs, the formation of endosperm is 
almost sure to be initiated by a series of simultaneous free nuclear 
