59 cobs scored, only seven appeared to have indurated 
glumes; and all of these, on further study, proved to be 
slightly charred, and, as a consequence, hardened. Of 17 
cobs of Late Nal-Tel, nine had distinctly lignified glumes. 
Another characteristic of teosinte-contaminated maize 
is the manner in which the floral structures separate from 
the rachis. In pod corn and in races of ‘‘pure’’ maize, 
the breakage occurs below the lower glume, leaving the 
rachis completely exposed. In maize strongly contami- 
nated with teosinte, the lower glumes are, as in teosinte 
itself, indurated like the rachis and tend to remain firmly 
attached to it, while the upper glume with the lemmas 
and paleas are easily separated from the cob. Such cobs, 
which have lost the upper glumes, lemmas and paleas, 
but have retained the indurated lower glumes, have the 
appearance of coarse rasps with stiffteeth projecting from 
the surface approximately at right angles. 
Most of the ears of Late Nal-Tel, as well as those of 
Dzit- Bacal, show to a discernible degree this type of dis- 
articulation, which is characteristic of teosinte-contami- 
nated maize. The majority of the cobs of Early Nal-Tel 
show the disarticulation characteristic of ‘‘pure’” maize. 
It is not possible, from the limited number of cobs 
available, to draw final and complete conclusions regard- 
ing the sequence of maize types grown by the La Perra 
cultivators. The data, so far as they go, are consistent 
with the hypothesis that the early tenants of the cave 
grew only one race of maize, Early Nal-Tel, a “‘pure”’ 
maize, uncontaminated by teosinte, and which had its 
origin in the south. Later occupants of the cave grew 
three new types, Late Nal-Tel, Dzit-Bacal, and Breve 
de Padilla, two of which have affinities with the maize 
of the Maya region and also show evidence of teosinte 
introgression. 
The data are also consistent with those from other 
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