a few dominant characters, or is concealed by the action 
of inhibitors. From a few selected ears of lowland Boli- 
vian corn nearly all the variations found in the valleys 
and highlands could be produced, as well as variations 
which are found in no other place but the lowlands. 
VARIATIONS IN THE NATURE OF THE EAR 
The structure of the maize ear has, in the past, been 
poorly understood by many botanists, probably because 
it is difficult to study the mature and woody ear. Re- 
cently, the work of Weatherwax (1985), Anderson (1944) 
and Mangelsdorf (1945) has done much to demonstrate 
the true nature of its structure, but the general opinion 
persists that the origin of the ear must have been unique 
and nearly miraculous. That this is not the ease is evi- 
denced by the fact that ear-like structures may be found 
in grasses which normally do not bear them. 
St. Augustine grass, Stenotaphrum secundatum (W alt.) 
O. Kuntze, a member of the Paniceae, usually has two 
rows of solitary fertile spikelets in alveoli on a flattened 
corky rachis. A variation occasionally found (although 
not as common as one with paired spikelets, one sessile 
and the other pedicellate) has four rows of alveoli on a 
much broadened and thickened rachis which has little 
tendency to disarticulate. 
In the genus Trichachne, also in the Paniceae, there 
is an even more striking resemblance to the maize ear. 
This does not imply that this grass is concerned in the 
evolution of maize, but merely shows that the develop- 
ment of the ear and tassel as female and hermaphroditic 
or male inflorescences is not as difficult as might be 
thought. In this genus there may occur the usual nor- 
mal plants with ordinary hermaphroditic inflorescences, 
plants with a lateral ‘‘ear’’ and a terminal hermaphrodi- 
tic inflorescence or tassel, and plants with ‘‘ears’” borne 
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