324 ANNUAL REPORT SMITHSONIAN INSTITUTION, 195 4 



lationships was no doubt slow and torturous. Primitive man learned 

 not only to collect and plant the seeds but to care for them in various 

 ways. He learned how to store them in the interval between collect- 

 ing and planting, and how and where the planting should be done. 

 He observed that when planted in some organic waste, the plant grew 

 better and bore more seeds and fruit. He became aware of differences 

 in the various propagules and selected for planting those which ap- 

 peared most desirable to him. These were the beginnings of horti- 

 culture and agriculture. 



As the primitive hunters populated the continent of their origin, 

 some groups migrated to other continents when opportunities arose. 

 A land bridge once existed from Africa across Sicily to Italy, over 

 which plants and animals, including early man, probably migrated. 

 Owing to the vast accumulation of water in the form of glacial ice, 

 sea levels were lowered to such an extent that land connections were 

 possible between Siberia and North America in the area of Bering 

 Strait. Bands of Asiatic hunters entered Alaska by this route, even- 

 tually populating both North and South America. The most direct 

 route would cover more than 5,000 miles from the Arctic through 

 tropical climates, establishing a great number of primitive cultures, 

 eventually leading to the establishment of the classic civilizations of 

 the Incas, Mayas, and Aztecs, within a period of about 15,000 years. 

 Though fantastic, this is based on the best inferences of archeologists 

 and geologists. 



The movement of the Siberian primitives into North America must 

 have been slow, perhaps taking many human generations. They came 

 from a cold northern region which probably had no agricultural 

 plants. There is no evidence of even a single species of domesticated 

 seed plant having arrived from Europe, Africa, or Asia in pre- 

 Columbian times. It is possible that man arrived in North America 

 before there were any domesticated plants in Asia or elsewhere, and 

 that domestication of plants in this hemisphere may have occurred 

 more or less simultaneously with that of the Old World. As these 

 people moved into the Americas they came in contact with a vast new 

 seed-plant flora with geneplasms very different from those known to 

 their ancestors. The Indians are known to have made use of over a 

 thousand species of native plants in what is now the United States. 

 Out of these only the sunflower and Jerusalem artichoke can be re- 

 garded as domesticated. However, many species were added to the 

 list from Mexico, Central America, and South America. 



DOMESTICATED PLANTS NATIVE TO THE AMERICAS 



A partial list of the more important plants domesticated in pre- 

 Columbian times may help us visualize and appreciate the efforts of 



