MULTIPLICATION. 85 
frequently absent without the process of reproduction 
being impaired by their absence. 
The process of fertilization may be described in general 
terms as follows :—The ovule contains, in a cell just be- 
neath the skin at its summit, one special piece of pro- 
toplasm, the ‘‘ germ,” which is destined to develop into 
the embryo plant. The pollen-cell consists of an outer 
coat and an inner lining ; the outer coat bursts, and the 
inner protoplasmic lining is protruded in the form of a 
tube, which passes down between the cells of the stigma 
and style, growing in length and feeding as it goes, like 
a parasitic fungus, on the contents of the cells of the 
style, until it reaches the ovule and comes into close 
proximity to, if not actually into contact with the germ. 
In consequence of this action a cell-wall is formed around 
the germ, which latter divides and subdivides in various 
directions, the result of the subdivision being the forma- 
tion of an embryo plant, as mentioned at p. 74, while 
the ovule covering the embryo ripens into the seed. The 
germ is thus fertilized by the pollen or sperm-cell, and 
unless the two come in contact, the formation of the 
embryo plant does not take place. 
Cross Fertilization.—It has been mentioned that the 
flowers with which the farmer is concerned have for the 
most part their stamens and pistils in the same flower 
(hops are an exception), and therefore they may be de- 
scribed as structurally hermaphrodite. It does not, how- 
ever, follow that they are functionally hermaphrodite— 
that is, that the pollen-grain of any particular flower 
fertilizes the germ-cell of the same flower. As a matter 
of fact, the reverse usually happens, and the pollen of 
*In the hop, the stamens and pistils are in separate flowers upou 
different plants. The farmer in the United States will find that the 
stamens and pistils are in different flowers upon the same plant in In- 
dian corn, pumpkin, squash, and all other plants of that family. 
