CHAPTER XXI. 



REPRODUCTION. 



I. The physiological processes previously discussed have been 

 concerned with the maintenance of the life of the individual 

 plant. It is now necessary to consider the process of reproduc- 

 tion, or the power of giving rise to new and separate individuals, 

 which is one of the most characteristic peculiarities possessed by 

 all living organisms. 



Among flowering plants two distinct modes of reproduction 

 are met with, namely, (i) vegetative reproduction and (ii) sexual 

 reproduction. 



VEGETATIVE REPRODUCTION. 



2. The essential feature of vegetative reproduction consists 

 in the separation either naturally or artificially of portions of the 

 vegetative organs of the parent, each detached part subsequently 

 developing into a new and complete individual plant. A good 

 instance of natural vegetative multiplication is seen in the potato. 

 Thin underground rhizomes grow out from the parent plant and 

 become thickened and form tubers at their tips ; at the end of 

 the summer the parent plant dies and leaves only the tubeis, 

 which in the following year develop into new separate plants. 

 Almost all plants with underground branching rhizomes behave 

 in a similar manner ; the older main portions die off and leave 

 the young lateral rooted branches to carry on their existence 

 as separate individuals. 



The buds on the stolons or runners of the strawberry and 

 creeping crowfoot (Fig. 21) become rooted to the ground 

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