(borne in pairs at four ranks of cupules) instead of the 12 
to 16 rows which characterize the older race. The shape 
of kernel is also different, being wider than deep rather 
than deeper than wide. In addition, the shape of the 
cupule is definitive. The ratio of cupule width/internode 
length is about two in Maiz de Ocho in contrast to the 
more narrow cupules of Chapalote, especially near the 
tip of the cob where the ratio is close to one. 
THe MaIze FROM THE BR-45 SIre 
The maize from BR-45 consisted of five broken and 
eroded cobs. ‘The kernel row number, cupule width and 
internode length of these specimens was measured in 
order to establish their racial identity (Table I). One of 
the cobs represented the race Maiz de Ocho and the other 
four were from its hybrid, Pima Papago. The eight- 
rowed cob could be a segregate out of the hybrid. In 
any case the hybrid was most abundant. The early ac- 
ceptance of the hybrid may be due to its rapid adaptation 
through the segregation of favorable genes from its in- 
digenous parent, Chapalote. he increased vigor and 
productivity associated with such a wide cross must have 
promoted its spread, probably far ahead of the Maiz de 
Ocho parent. 
The cultivation of the productive races of maize, Maiz 
de Ocho and Pima Papago by the people at BR-45 
seems to have bound their way of life to farming. Serv- 
ing these people as a major source of food, they became 
dependent upon it. Subsequently after a protracted dry 
period they abandoned the mesa for sites nearer the river 
which provided the moist soil necessary for the growth 
of their maize. After abandonment, the cobs of Maiz de 
Ocho and Pima Papago and other debris on the ridge 
sites became buried under the sands of time until the 
present excavation. Previously when their ancestors with 
[ 822 ] 
