12 THE ORIGIN OF PLANT AND ANIMAL CHILDREN 
The fertilized egg cell remains in the pistil, receiving nourish¬ 
ment from the plant’s food and growing into a seed, which is 
a young plant with stored-up food, ready under favorable 
conditions to sprout and grow. 
The blossom and honey of the flower serves to attract in¬ 
sects, which by chance rub against the pollen of one flower 
and frequently carry it 
adhering to their rough 
bodies to another flower 
of the same kind. There 
it may rub off on the 
sticky end of the pistil 
and fertilize the egg cell. 
The pollen of some flow¬ 
ers fertilizes the egg of 
the same individual, a 
process called dose fer- 
Figure 11. — A Diagram of a Flower, tilization; but in most 
C, the corolla, the colored leaves of the P lantS , there are devices 
flower ; S, a stamen, from whose sacks by which this is pre¬ 
pollen is brought to the pistil; P, the pistil, vented and the carrying 
kind is insured, a pro¬ 
cess called cross fertilization. Cross fertilization is thought 
to give stronger plants, and so is the method most favored 
in nature. 
In all the higher animals and in many plants and lower 
animals cross fertilization is made necessary by the fact that 
the sperm cells and the egg cells grow in separate individuals, 
the male producing the sperm cell and the female the egg 
cell. We have seen that in flowers a common method of 
bringing these two cells together for fertilization is by en¬ 
ticing insects to carry the pollen. In most animals the op¬ 
posite sexes have an instinct to seek one another. 
