pothesis of the hybrid origin of teosinte, by no means 
prove its validity. 
‘TRIPSACUM 
Slightly less puzzling, since it still grows in 'Tamauli- 
pas, is the presence of 7'ripsacum in the refuse of the 
Canyon Infiernillo caves. Seeds of 7’7ripsacum, like those 
of teosinte, are nutritious but are difficult to remove from 
the bony shells in which they are enclosed. They are not 
especially promising as a source of food yet must some- 
times have been gathered for this purpose. Gilmore 
(1931) found fruits of 7’77:psacum in the prehistoric refuse 
of a cave in the Ozarks. 
Five specimens of 7'ripsacum were found in the refuse 
and these included both staminate and pistillate spikelets 
(Plate XIII, B). We were not able to make positive 
identification with respect to species although one of the 
spikes seemed to bear a somewhat closer resemblance to 
T’. zopilotense—which has not been collected in Tamau- 
lipas—than to 7. dactyloides which occurs there now. 
SUMMARY 
1. The vegetal remains uncovered in the refuse in 
three once inhabited caves in southwestern Tamaulipas, 
Mexico, are of particular interest in containing specimens 
of all three of the American Maydeae: maize, teosinte, 
and T'ripsacum as well as hybrids of maize and teosinte. 
2. The collection, comprising 12,014 specimens, in- 
cluded virtually all parts of the maize plant: stalks, 
leaves, husks, cobs, and tassels as well as chewed quids 
of various parts. 
3. The corn is predominantly of the race Chapalote; 
about two thirds of all of the identified cobs are assigned 
to this race and its several subraces. 
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