294 PHARMACEUTICAL BOTANY 
Fic. 221.—Development of the female gametophyte in an angiosperm. A, 
lengthwise section through a pistil showing a single inverted ovule within the 
locule of the ovary. The embryo sac is in the center of the ovule surrounded by 
the nucellus () and the two integuments (1) better shown in C. Note how the 
pollen tube reaches and enters the micropyle of the ovule. _B shows the develop- 
ment of the eight nuclei in the embryo sac. C shows the mature female gameto- 
phyte and the tip of the male gametophyte; the former containing eight nuclei 
and the latter containing only three. AP, antipodal nuclei; E, egg nucleus; EN, 
two polar nuclei fusing to form endosperm nucleus; J, integuments; WV, nucellus; 
S, sperm nuclei. (After Atwood.) 
Fic. 222.—Development of the embryo. This figure is a continuation of the 
preceding. D shows the antipodal cells (AP) disappearing, and the fusion of the 
two sperm nuclei with the endosperm nucleus (ENV) and the egg nucleus (£). 
The remains of the pollen tube (P) are seen in the micropyle (M). £ shows the 
developing embryo with its suspensor (5) and the endosperm (END). F shows 
the young embryo and its parts. C, cotyledons; PL, plumule; R, radicle. Note 
that the embryo is surrounded by four coats. END, endosperm; .V, nucellus; 
1 and OF, inner and outer integuments. His the hilum. (After Atwood.) 
aac 
