64 



INTRODUCTION TO PLANT GEOGRAPHY 



CHAP, 



conditions, grows into the new generation, so completing the Hfe- 

 cycle. Thus, in such sexual reproduction-cycles, the chances of 

 dispersal of individuals are limited to the seed, although the pollen 

 grains can transport heritable characters. Nor do Gymnosperms 

 normally possess effective modes of asexual reproduction, except for 

 such vegetative methods as ' layering ', which involves the rooting 



