PHANEROGAMIA. 229 
486. The embryo-sac is an enlarged cell, at maturity con- 
taining several rounded masses of protoplasm, one of which 
is the germ-cell. As the tissues of the ovule-body can suf- 
Fia. 130.—Diagrammatic longitudinal sections of ovules. k, the body of the 
ovule, with its embryo-sac, em; ai, the outer, and 7, fhe inner, coat; m, the 
opening in ovule-coat (micropyle); c, the base of the ovule; f, the ovule-stalk; 
A, a straight ovule; B, an inverted ovule: the long stalk, 7, has fused with the 
outer coat of one side of the ovule. 
ficiently nourish the germ-cell, there is little or no develop- 
ment of the first stage (prothallium) at this time, and there 
is an almost complete suppression of the archegone-walls. 
. wo 
Fic. 131.—4, a longitudinal section of an ovule of the Pansy, after fertilization; 
a and i, coats of the ovule; p, pollen-tube; e, embryo-sac, with the very young 
embryo at one end and free endosperm-cells at the other. B, apex of embryo- 
sac, e; eb, very young embryo of four cells. 
487. Fertilization takes place as follows: The pollen- 
cell, resting upon the moist surface of the stigma, germi- 
nates, and its tube penetrates the soft tissues of the stigma 
and style, finally reaching the cavity of the ovary, where 
