verse conditions, yet when seeds are planted in a more 
favorable environment, as in material from Lake Titicaca 
planted under irrigation in Cochabamba, there is little or 
no change. The specimens of maize Anderson described 
from Rio Loa, Chile (1948), as well as most of the pre- 
historic material discovered within the present range of 
the race, falls within the range of variation of Altiplano 
maize. Like most of the prehistoric material, Altiplano 
maize probably does not represent a primitive type but 
may be one of the early developments which could with- 
stand the environment in which it is grown and may in- 
dicate the nature of the primitive type from which it 
was developed. 
Uchukilla maize 
The name, Uchuhilla, is applied in Bolivia and Peru to 
a small crystal-white flint grown on the slopes of valleys 
at about 2600 meters altitude. The race includes, how- 
ever, some flour and semi-flint varieties, usually yellow 
and often red, which are known locally by other names. 
The plants are small and mature earlier than other races 
in the same district, usually requiring 50 days from time 
of planting to the appearance of the silks. The ears 
(Plate XXXVI, C, D, E) are small, with 8 or 10 
straight rows of grains. These grains are widest about 
two thirds of the distance from the base to the tip, and 
frequently very slightly beaked, pointed or dented. Ears 
of Altiplano maize which have low row numbers and a 
less spherical ear shape than usual approach Uchukilla in 
appearance. It is nearly always possible, however, to dis- 
tinguish the few and distinct rows of nearly diamond- 
shaped flattened grains of Uchukilla from the larger 
number of somewhat irregular rows of rounded or slight- 
ly pointed and imbricated grains of Altiplano maize. 
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