MULTIPLICATION. 81 
thorough ‘ripening, but that exposure to light is also 
requisite, a dull, cloudy summer, even if warm, being 
unpropitious to ripening, whether of fruit or grain. 
CHAPTER VI. 
MULTIPLICATION, 
Sub-division.— Intermarriage.— Buds, Branches, Tillering, Tubers.— 
Fertilization, Stamens, Anthers, Pollen, Pistil.—Mechanism of Fer- 
tilization. — Cross-Fertilization. — Transport of Pollen. — Insect 
agency.—Self-Fertilization.—Fertilization of cereals.— Hybridiza- 
tion.— Germination. 
Multiplication.—There are two special ways in which 
plants multiply. One is a mere process of extension or 
subdivision—a modified form of growth, in fact. The 
other is the result of the union or commingling of a por- 
tion of the protoplasm of one plant with a corresponding 
particle of another plant. In the lower plants, as they 
are designated, it is not even necessary that union of 
particles of protoplasm from different plants should be 
effected. The contents of one cell blend with the con- 
tents of another cell on the same plant, and the result is 
‘the formation of a seed or spore, by means of which the 
plant is reproduced. The first process of multiplication, 
by division, is called asexual, the second sexual, because 
it is a process of intermarriage requiring the co-operation 
of two distinct particles of protoplasm. In the very 
lowest plants these two particles present no appreciable 
differences, but in the higher plants and animals they 
present such differences as to enable us to distinguish 
one as male, the other as female. In the lowest plant 
the two particles are split off from the same mass of pro- 
toplasm, while in the higher plants the male element is 
formed from a different source from the female, 
