successful in producing seed than the maize. He attri- 
buted this ability of teosinte to ward off drought to the 
fact that it produces a succession of younger ears in clus- 
ters which eventually encounter the late season rains 
necessary for grain development. A situation in which 
this morphological type of resistance has been transferred 
to maize was observed this past summer at the Bussey 
Institution in the race Reventador, which seems to be a 
teosinte-contaminated descendant of Chapalote and has 
some similarities to the teosinte-contaminated form of 
Chapalote that was prevalent in the Southwest before 
A.D. 700. 
Apparently at about A.D. 700, a third element, the 
race of eight-rowed maize, Harinoso de Ocho, entered 
upon the evolutionary scene and conferred new benefits 
in the form of higher yield, easier milling and adapta- 
bility to a far greater range of environments. A re- 
examination of the earlier eight-rowed cobs from the 
Durango Basketmaker site described by Jones and Fon- 
ner (1954), has now revealed that their eight-rowed con- 
dition is probably a result of teosinte introgression into 
the race Chapalote. 
Some of the differences between eight-rowed cobs re- 
sulting from teosinte introgression into Chapalote, such 
as those from Durango, and this new eight-rowed race, 
Harinoso de Ocho, are apparent in Plate XX. The trip- 
sacoid element in eight-rowed Chapalote (figs. 1-4) is 
revealed by a combination of slender cobs which may be 
curved and have slender shanks with narrow, triangular 
shaped cupules and hard up-curved glumes. The Harin- 
oso de Ocho element (figs. 5-12) is manifest in thick 
straight cobs which are sometimes swollen at the base, 
thick shanks, wide cupules and wide, crescent-shaped 
kernels. In describing this race, Wellhausen et al. 
(1952), postulated that it was introduced into Mexico 
[119 ] 
