there is complete interfertility in maize varieties from 
all parts of America, it is logical to conclude that the one 
has been derived from the other. Segregates from maize- 
teosinte crosses and isogenic stocks developed by repeated 
backcrossing of such crosses to inbred strains of maize 
demonstrate that teosinte genes can produce the changes 
by which the two types are distinguished. All of these 
facts indicate, though they obviously do not prove, that 
a pure maize originating in South America and bearing 
ears characterized by whorled phyllotaxy and random 
arrangement of sessile and pedicellate spikelets has be- 
come modified by the introduction of Tripsacum (teo- 
sinte) germplasm to produce an ear characterized by 
spiral phyllotaxy and systematic arrangement of spike- 
lets. 
ACKNOWLEDGMENTS 
Tothe Massachusetts Society for Promoting Agricul- 
ture I am indebted for a grant, to be used in the study 
of maize varieties of Latin-America, of which this paper 
is an outgrowth. Professor Oakes Ames generously 
loaned me, from his personal library, the copy of Lyte’s 
Herbal from which Plate VII is reproduced. The draw- 
ings which illustrate the paper were made by Mr. Gordon 
Dillon. I wish to thank Dr. Edgar Anderson and Dr. 
Leon Croizat for allowing me to include certain of their 
unpublished observations. And I am especially indebted 
to Dr. R. G. Reeves for permitting me to read and to 
refer to his unpublished paper on the morphology of the 
maize ear; a paper which, except for the exigencies of 
war, would certainly have been published before mine. 
[72 ] 
