and Langham has found a similar situation in Durango 
teosinte. These facts suggest that the separation of useful 
from undesirable genes in Guatemalan corn may not be 
too difficult. In any case the possibility of utilizing in 
practical corn improvement this complex reservoir of 
potentially valuable germplasm is not one to be com- 
pletely overlooked or indefinitely postponed since Latin 
America is facing the same danger which the Corn-Belt 
has already met,—the extinction of potentially useful 
varieties as the result of widespread planting of a few 
selected types. 
SUMMARY 
1. Chromosome knob counts, in 162 varieties from 
thirty-eight localities in western Guatemala, showed a 
range in knob numbers from one to sixteen. 
2. All of the eighteen knob positions known in maize 
and in addition three positions not previously reported 
were encountered. 
3. The greatest diversity was found in a small area in 
the Department of Huehuetenango where low-knob and 
high-knob varieties occur in close proximity. This is also 
the area in which teosinte is found growing in the wild. 
4. The maize of western Guatemala exhibits great 
diversity in external morphological characteristics, but 
plants with six knobs or less are uniform in having pubes- 
cent leaf-sheaths, a coarse seminal root system and in 
susceptibility to lodging and smut. These varieties are 
found only at altitudes of 6500 feet or more. 
id 
5. The number of chromosome knobs is associated 
with various characteristics which may have been de- 
rived from ‘Tripsacum. 
6. The combined evidence suggests that a South 
American variety of maize—characterized by pubescent 
[ 247 ] 
