WEATHERWAX: THE EVOLUTION OF MAIZE Ba] 
teristic that is actually new, and, as Gernert suggests (14, p. 6), 
most of the results may be explained on a basis in no way con- 
nected with the original mutilation. As the theory stands, we 
can justly ask that the experiments be repeated successfully with 
more than one variety of maize, and the results interpreted on the 
basis of a more sound understanding of the morphology of the 
plant throughout its normal range of variation, before we consider 
this a substantiated explanation of the past history and present 
tendencies of the plant. 
Montgomery’s theory —Along with his explanation of the ear 
of corn as the homologue of the central spike of the tassel (24), 
Montgomery proposes a theory of evolution, which, while not 
worked out in full detail, is probably the most consistent solution 
of the problem yet offered. He considers maize a distinct genus 
codrdinate with teosinte, both having developed from a common 
teosinte-like ancestor. 
A THEORY BASED UPON MORFHOLOGY 
Exact knowledge of the past conditions being out of the ques- 
tion, the ancestry of the maize plant and the steps taken in its 
evolution can only be built up in theory from a study of the 
modern plant and its near relatives; and some attempts previously 
made in this direction have already been discussed. Any theory 
that is to receive serious consideration must be based upon, and 
consistent with, recognized facts; and, of two or more explanations 
of the same thing, the simplest and most direct is to be preferred. 
Several kinds of evidence are available for use in the study of 
maize; but morphology, the basic constructive factor of most of 
our theories of evolution, has never been utilized to the full extent. 
To be sure, the gross structure of this group of plants has several 
times been considered, but a morphological study that does not 
go to the bottom of the question is likely to mislead the investi- 
gator. The study of abnormal structures is always instructive, 
but it is more significant to find in the normal plant a morpho- 
logical basis for its abnormalities. Other considerations, such as 
may be occasioned by experiments in hybridization and selection 
for a few generations, constitute instructive checks on other 
methods; but they must not be over-emphasized as constructive 
