Cultivated Elementary Species 65 



ary type. But it is not very likely that such 

 partiality would occur often. The conception 

 that different tribes at different tunes and in 

 distant countries would have used the wild 

 plants of their native regions seems far more 

 natural than that all should have obtained 

 plants for cultivation from the same source or 

 locality. If this theory may be relied upon, 

 the origin of many of the more widely cultivated 

 agricultural plants must have been multiple, 

 and the number of the original elementary spe- 

 cies of the cultivated types must have been so 

 much the larger, the more widely distributed 

 and variable the plants under consideration 

 were before the first period of cultivation. 



Further it would seem only natural to explain 

 the wide variability of many of our larger agri- 

 cultural and horticultural stocks by such an in- 

 cipient multiformity of the species themselves. 

 Through commercial intercourse the various 

 types might have become mixed so as to make it 

 quite impossible to point out the native locali- 

 ties for each of them. 



Unfortunately historical evidence on this 

 point is almost wholly lacking. The differences 

 in question could not have been appreciated at 

 that remote period, and interest the common ob- 

 server but little even today. The history of 

 most of the cultivated plants is very obscure, 



