226 PLANT LIFE 



structure, the prothallus, on which the gametes 

 are ultimately produced. 



It is, however, impossible to appreciate the 

 significance of all this without some prelimin- 

 ary acquaintance with the behaviour of the 

 cell nucleus, and its relation to cell division 

 and cell organisation, which will form the 

 subject of the following chapter. 



CHAPTER XX 



THE CELL-NUCLEUS AND FERTILISATION 



IN order to be in a position to grasp the 

 essential facts of fertilisation, and their far- 

 reaching consequences on the organism in 

 general, it is necessary, as stated in the con- 

 cluding paragraph of the preceding chapter, 

 to learn something of the structure of the 

 nucleus. Moreover, a study of the nuclear 

 processes will enable us to apprehend the 

 meaning of some of the most constant and 

 singular features which, in the form of alterna- 

 tion of generations, are of such widespread 

 occurrence in the vegetable kingdom. 



