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 teen 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 upon 

 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. 



