252 



COLLEGE BOTANY 



at a very early date, but received a great impetus from the Aryan 

 migrations from Asia about 2500 or 2000 years b.c. (Fig. 116). 

 Ancient Agriculture in America. — Agriculture iu the west- 

 ern hemisphere is not as old as. in the eastern hemisphere, but 



Fig. 116. — Map showing the origin of some of our most important grain crops. 



was practiced by aborigines long before the coming of the white 

 man. It reached its highest development in Mexico, Central 

 America, Peru and adjacent regions. We are indebted to 

 America for many of our most important agricultural plants, 

 such as com, potatoes, tomatoes, tobacco, cacao, sweet potatoes 

 and manv others. 



