396 ORIGIN OF CULTIVATED PLANTS. 



the discovery of America.^ Now, at that epoch the 

 number of varieties was already considerable, which 

 proves a much more ancient cultivation. 



Experiments in sowing varieties of maize in unculti- 

 vated ground several years in succession would perhaps 

 show a reversion to some common form which might then 

 be considered as the original stock, but nothing of this 

 kind has been attempted. The varieties have only been 

 observed to lack stability in spite of their great 

 diversity. 



As to the habitation of the unknown primitive form, 

 the following considerations may enable us to guess it. 

 Settled populations can only have been formed where 

 nutritious species existed naturally in soil easy of 

 cultivation.. The potato, the sweet potato, and maize 

 doubtless fulfilled these conditions in America, and as the 

 great populations of this part of the world existed first in 

 the high grounds of Chili and Mexico, it is there probably 

 that wild maize existed We must not look for it in the 

 low-lying regions such as Paraguay and the banks of the 

 Amazon, or the hot districts of Guiana, Panama, and 

 Mexico, since their inhabitants were formerly less nume- 

 rous. Besides, forests are unfavourable to annuals, and 

 maize does not thrive in the warm damp climates where 

 manioc is grown.^ On the other hand, its transmission 

 from one tribe to another is easier to comprehend if we 

 suppose the point of departure in the centre, than if we 

 place it at one of the limits of the area over which the 

 apecies was cultivated at the time of the Incas and the 

 Toltecs, or rather of the Mayas, Nahuas, and Chibchas, 

 who preceded these. The migrations of peoples have 

 not always followed a fixed course from north to south, 

 or from south to north. They have taken different 

 directions according to the epoch and the country.' The 



• Rooliebrune, Becherehes Ethnographiques siir les Sepultures Piruviennes 

 d'Ancon, from an extract by Wittmack in Uhlworm, Bot. Central-Blatt, 

 1880, p. 1633, where it may be seen that the bnrial-gruund was used before 

 and after the discoveyy of America. 



' Sagot, OuH. des Oir^ales de Ig, Quyane Franf. (Jcmm. de la 8oc. 

 Oentr. d'Hortic, de France, 1872, p. 94), 



* De Naidaillao, in his work entitled ie» Premiers Homm^a et les 



