(‘‘brown’’) aleurone and a white flint which belong to 
the Guarani race of maize. 
Highland maize is susceptible to smut just as the va- 
rieties classified by Mangelsdorf and Cameron (1942) as 
Andean were susceptible. Perhaps there is some connec- 
tion between the use of corn smut as food, a common 
practice in the highlands, and its occurrence. Lowland 
maize grown at an altitude of 2,500 meters in Cocha- 
bamba, Bolivia, was rarely attacked by smut. On the 
other hand, lowland maize grown in Cochabamba was 
badly damaged by rust. Coroico maize was most severely 
infested, then Guarani and least of all the Coastal Flints 
and the highland races. Several commercial yellow dent 
inbreds from the United States were so badly covered 
with rust that they died before tasseling. 
Races or SourH AMERICAN MAIZE 
Coroico maize 
Coroico maize is the most unusual race known so far. 
Some of its characteristics are found in other races, es- 
pecially in Guarani (Plate XX XV, C, D, EK, F, G) but 
these are encountered less frequently in areas remote 
from Coroico, Bolivia, and no ears of this race have 
been discovered more than a short distance from Coroico. 
At present the race is restricted to those ears which have 
the alternate arrangement of alicoles or which approach 
this condition and have enough of the other characters 
(slender flexible ear, spikelet pairs on a pedestal, brown- 
orange aleurone and brownish cob) to distinguish them 
definitely from Guarani which is to the south and east, 
and from mixtures with the Coastal Tropical Flints, 
which are found in parts of eastern Ecuador, and in Brazil 
as far east as the states of Goias, Maranhao and Ceara. 
The town of Coroico is in a transition area close to the 
division between the highland and lowland Indian groups 
[ 278 | 
