118 SOUTH AFRICAN BOTANY 
When the ovule is fully developed the nucleus of the 
embryo-sac divides up into two. These move to each 
end of the embryo-sac, and there each divides into four. 
yinicropyle 
Fria. 68.—Orthotropous Ovule, Show- Fig. 69.—Anatropous 
‘ jng Contents of Embryo-sac. Ovule. 
Then three of the nuclei at the micropylar end of the 
embryo-sac become surrounded by protoplasm and form 
asynergile 
Wy-- ovum 
mitropyle’ —\ Y{— funicle \ _ secondary 
ey F dat Za nucleus 
_antipodal 
Fia. 70.—Campylotropous 
Ovule 
cells 
Fia. 71.—Development of 
Embryo-sac. 
a. Embryo-sac with nucleus 
undivided. b. Nucleus 
divided into two. e. Hach 
nucleus divided into four. 
d. Appearance of erubryo- 
sac when ready for fertil- 
ization, 
three cells. The largest is the oosphere, ovum or egg- 
cell, the two smaller are the Synergidae (helping cells), 
