402 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1937 



The mutation theory affords an easy means of overcoming the time 

 factor since by assuming a single mutation it is possible to originate 

 maize from teosinte or for that matter from any other grass within a 

 single year. Of course, no one proposes that maize arose in quite 

 this abrupt fashion. However, it has been suggested that maize 

 arose through a series of mutations, each leading to a more maize- 

 like plant. Thus, if a mutation took place in teosinte such that 

 seeds of useful size were produced, man would immediately enter the 

 picture to preserve such plants. In time a second mutation might 

 produce paired female spikelets such as are found in com, and by 

 further mutations a cob could have been derived, and so on until 

 all the differences between maize and teosinte were obtained. These 

 mutations need not have been gross changes but each one preserved 

 must have increased the value of the plant to man . 



Tlie evidence against anything approaching the origin of maize 

 through the preservation of relatively large mutations is threefold. 

 First, none of the intermediate stages, none of the halfway corns, 

 have been found in the earliest burials. This is a minor objection 

 if the mutations took place in remote times but it is well to bear in 

 mind because perforce it places man in the New World in very an- 

 cient times. Not so ancient it is true as would be required if com 

 were derived from teosinte by the orthodox means of selecting small 

 variations or small mutations, but measurable in thousands of years. 



Second, com everywhere is botanically identical. The com of 

 North America is indistinguishable in the features which make it 

 com from that of South America. For those who hypothecate a 

 relatively few major mutations this hemispheric identity of com is 

 unfortunate. The first mutation making teosinte or any other com 

 ancestor useful to man would have started the plant upon its jour- 

 neys, and the succeeding mutations that led to the building up of 

 maize would have occurred at widely scattered points and over cen- 

 turies of time. Each would spread from its point of origin but dif- 

 ferent combinations of these mutations would be expected at different 

 points on the periphery of com distribution. Widely separated 

 regions of the New World would have had widely different species 

 of com. We have seen that such is not the case. To account for 

 the obvious fact that com is com wherever found we must assume 

 either that enough time has elapsed since the last important muta- 

 tions to permit them to have become thoroughly incorporated in the 

 species or the less likely assumption can be made that all the muta- 

 tions eventually occurred at some one place and the plant was dis- 

 tributed from that pomt. 



Although mutations have not been found in teosinte today, no 

 doubt they do occur but not of an order of magnitude that would 

 suggest a development into maize. 



