2IO PLANT LIFE. . 



duced by some plants are exceedingly complex and varied, 

 while others form reproductive liodies in very direct ways. 

 The reproductive bodies themselves are generally very sim])le. 

 In addition to complex reprodu(.ti\'e organs, there are some- 

 times accessory j)arts by which the plant adapts its reproduc- 

 tive functions to the conditions under which it lives. Among 

 these accessory structures are many, as among the llowers of 

 seed plants, by which the aid of other plants or animals is 

 secured. 



300. Vegetative and sexual reproduction. — In all the 

 diversity of organs and processes two chief methods may be 

 distinguished, called vegelalwe reprudiictiun and sexual repro- 

 duction . 



Vegetative reproduction consists in the formation of repro- 

 ductive bodies by processes of growth only. The modes in 

 which they arise are varied in detail, but consist essentially 

 in the production by the parent of a body, unicellular or 

 multicellular, which at maturity de\'elops, under suitable 

 conditions, into a new plant. 



Sexual reproduction consists in the formation of reproduc- 

 tive bodies by the union of two specialized rells, neither of 

 which alone is capable of developing into a new plant. 



