locus. There is no doubt, however, that in nature teo- 
sinte introgression also has had its effects superimposed 
upon these. One of the most important of these effects 
is a toughening and hardening of the tissues of the glumes 
and rachis. Had this not occurred, the massive rachis and 
the short glumes of modern varieties could scarcely have 
come into existence. 
The diagram of modern Dent corn (Plate XXVIII, 
fourth row) illustrates the lengths to which the evolu- 
tionary trends revealed by the Bat Cave cobs have now 
gone. ‘The rachis has become massive and capable of en- 
closing an enormous vascular system. The glume zone 
has been reduced to a minimum, but the glumes have 
become more or less indurated. The distance between 
the surface of the rachis and the base of the kernels has 
been drastically shortened. The entire ear has become an 
extremely efficient grain-bearing structure, one which, 
to be sure, would scarcely be capable of surviving in the 
wild, but which in a man-made environment has no peer 
among cultivated cereals. Maize is, in many respects, the 
most efficient producer of foodstuffs among the cereals, 
and one of the factors in that efficiency is undoubtedly 
the nature of its pistillate inflorescence. 
THE PLACE OF ORIGIN oF MAIZE 
The evidence from Bat Cave sheds no new light upon 
the place of origin of maize as a wild plant. It seems 
scarcely possible that maize could have existed as a wild 
plant in the vicinity of Bat Cave since the present and 
past vegetation of this region is made up largely of xero- 
phytic or near-xerophytie species. Furthermore, there is 
no more reason for suspecting that maize originated here 
than for believing that beans and squashes also had their 
origin in this region. 
Mangelsdorf and Reeves (1939) concluded that maize 
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