A Botanical and Economic Study. 



93 



gives the altitudes of the places, and the mean temperature 

 and mean rainfall for the months of April, May, June, July, 

 August, September and October, 1889: 



The temperature of all the places is favorable to the growth 

 of the wild cereal, but the rainfall in Aguas Calientes, Saltillo, 

 San Luis Potosi and Zacatecas is so small that these places 

 are discarded, as being outside of the limit of the possible 

 original home of the wild form. Mazatlan, on the Pacific 

 coast, is also omitted, because it is hardly probable that corn 

 was a sea-side pbnt. The other stations answer the require- 

 ments better. On consulting a map of Mexico, it is seen 

 that Guadalajara, Guanajuato, Huezutla, Leon and Puebla lie 

 below the twenty-second degree of north latitude, at eleva- 

 tions ranging from 11 28 feet, that of Huezutla, to 6520 feet, 

 that of Puebla. From other considerations (ante), it is likely 

 that maize was a highland plant ; Huezutla is therefore dis- 

 carded, as below the limits in altitude. The other places lie 

 above a level of 4500 feet, and in all likelihood the original 

 form of corn grew at this altitude and higher. The area is 

 narrowed, therefore, to the region near Guadalajara, Guana. 



