amount of new information about maize has been ob- 
tained and, for the most part, it fits the Mangelsdorf and 
Reeves hypothesis better than any other. It is now pos- 
sible at least to outline the characteristics of some of the 
major races of South American maize (Coroico, Guara- 
ni, Coastal Tropical Flint, Altiplano, Uchukilla, Valle, 
Cuzco) as a result of this study. 
At various times in the past, scientific names have 
been proposed for certain groups of South American 
maize. Most numerous are the names based on collec- 
tions made by the Russian expeditions of 1925-26 (Ku- 
leshov 1980, Kozuhkov 1985). While these names may 
have been of some value in calling attention to certain 
peculiarities, they do not group the variations into prac- 
tical working divisions or reflect natural relationships. 
As Anderson and Cutler pointed out (1942), it is too 
early to attempt an accurate classification of maize since 
good material is still lacking from critical areas, and some 
of the material now available is as yet incompletely 
studied. Also, many of the characters essential to a care- 
ful and conservative analysis of the relationships of races 
in Zea are imperfectly known and rarely utilized. To 
propose taxonomic categories and increase the confusion 
of synonymy which already clouds Zea Mays L. is un- 
wise while critical studies are still in their primary stages. 
CONSTANCY AND CHANGEABILITY OF MAIZE VARIETIES 
Scarcely less amazing than the great diversity of maize 
which is familiar to all students of the plant is the fact 
that so many of the varieties cultivated today have re- 
mained constant over so long a period of time. Indian 
fields form plant populations where optimum conditions 
for the evolution of new races are present. Here are cen- 
ters where plants grow isolated from their relatives cul- 
tivated by other Indian tribes or by other divisions of 
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