cob for known teosinte introgression and correlating it to 
specific gravity. The archaeological material consisted of 
217 cobs from Richards’ Caves. Since induration is a 
subjectively determined character, all estimates were 
made by one person. Specific gravity determinations 
were made as with the modern specimens. Here again, 
the difference is significant, although the increase in spe- 
cific gravity is not so great and is limited to the highest 
grade of induration. The curve expressing this relation- 
ship (Table I) would resemble that used by Anderson 
and Erickson (1941) to illustrate their hypothesis of anti- 
thetical dominance (a hypothesis suggesting that modi- 
fier complexes with sharp threshold effects contro] domi- 
nance of certain characters in wide hybrids). 
Tests for Lignification in Teosinte Derivatives 
and Archaeological Cobs 
Since cellulose is easily dissolved by concentrated sul- 
phuric acid while lignified tissues are resistant, treatment 
with this acid is recognized as a specific test for lignin. 
It has been found that, when cobs of teosinte derivatives 
are so treated, they lose all of their tissues except the 
rind and cupules of the rachis and the lower glumes. 
When archaeological specimens are subjected to the same 
treatment, immersed for twenty-four hours in sulphuric 
acid, the Tripsacoid cobs remain almost intact, while the 
pure maize cobs disintegrate to a delicate framework of 
cupule margins (Plate XX VII). 
It has already been mentioned that both modern and 
archaeological Tripsacoid cobs have a higher specific 
gravity than the non-Tripsacoid cobs. None of these 
facts in itself proves that the cobs in question are a pro- 
duct of maize-teosinte hybridization; but, together, they 
provide a reasonable presumption that such might be the 
case. 
{ 105 | 
