204 PLANT LIFE 



CHAPTER XVIII 



VEGETATIVE REPRODUCTION 



REPRODUCTION, in its simplest and most 

 primitive form, is one of the most obvious 

 results of growth. It represents, after a 

 fashion, and in a certain tangible form, the 

 balance of profit over expenditure on the 

 part of the individual, which is applied to 

 the extension of the business of the species 

 or race. But the process is not a simple one. 

 When a unicellular plant, Chlamydomonas 

 for example, has reached a certain size, the 

 protoplasm ceases to grow. It divides, and 

 the products of this fission, which may be 

 repeated several times, separate from each 

 other as new and independent individuals. 

 Nothing is left of the old organism, it has 

 simply split up into a number of smaller ones, 

 In other words, the nutritional processes which 

 enabled growth to proceed have prepared 

 the way for, and have then given way to, a 

 new set of chemical processes, and these 

 result in the cleavage of the mass into smaller 

 parts. This cleavage, or cell-multiplication, 

 may be started in several different ways, but 

 the method most often encountered in nature 

 clearly depends on factors which are them- 



