EXPLANATION OF THE ILLUSTRATION 
Piare XXIII. A series of cobs from the various 
levels in Cebollita Cave. The original Chapalote 
maize (cob A) of Level 5 has some non-carbonized 
counterparts (cob B) in Level 4. Note the soft 
glumes of cob B. Level 4 also contains many small 
highly Tripsacoid cobs (C, D) similar to segregates 
of experimental hybrids between maize and teo- 
sinte. Although Level 3 (cobs E, F, G) marks the 
beginning of a progressive decrease in the indura- 
tive effects of the teosinte introgression, the varia- 
bility which it had introduced continues to increase. 
Finally in Levels 2 and 1, there is almost complete 
recovery from the detrimental effects of the intro- 
gression and many of the cobs (H, I) are larger and 
probably more productive than the original Chapa- 
lote maize. About one half natural size. 
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