206 PEARLS AND PEBBLES. 



It is known that the mingling of pollen from flowers 

 of the same natural order, through the agency of bees 

 and other winged insects, is the cause of the great- 

 variety of speeies which we find in plants of the same 

 family ; thus the different races of plants can be traced 

 back to their natural orders, including the genus and 

 species of every family in all its variations. 



