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- 
