THE PLANT AND ITS PARTS. 13 



keeps pace with the growing seed and embryo within it ; 

 so that when it is quite ripe, it is called the Pericarp, 

 and takes on a variety of forms, as shown by the innumer- 

 able sorts of Fruits in nature. The application of the 

 pollen to the stigma is called Pollination, and the forma- 

 tion of the embryo is called Fertilization. The former 

 may take place, but the latter does not always follow. 



There are different ways by which pollination may 

 be secured. First, by means of the wind. This applies 

 to several plants with inconspicuous flowers, which 

 have the pistil in one, and the stamens in another 

 flower. This is called " Wind-pollination." Secondly, 

 the pollen may be unwittingly carried off by bees and 

 other insects ; sometimes even birds, as the South 

 African sun-birds do it ; and then, when they visit 

 other flowers of the same kind, the stigma hits them 

 just where the pollen will be on their heads or else- 

 where. This is called the Crossing of flowers, and is 

 described as Insect-pollination. 



Lastly, the pollen may be applied to the stigmas of 

 the same flower in consequence of the anthers being 

 situated in close contact with them. Such is called 

 Self- or Close-p)ollination. 



If it be asked which of the three kinds of pollina- 

 tion is the best, the question is, what do we mean by 

 " best " ? There are only two matters which concern a 

 plant — one is to live a healthy life till it dies, and then 

 to leave an abundance of good seed. 



