sirable to review the previous evidence and hypotheses 
which bear upon the problem. Only the essential features 
of the earlier hypotheses will be considered here since the 
rather extensive literature on the subject has been tho- 
roughly reviewed in recent years by several writers. The 
reader is referred to the papers of Weatherwax (19), 
Mangelsdorf and Reeves (13), and Reeves (15) for addi- 
tional details. 
HisroricaL CONSIDERATIONS 
The Maize Ear Described 
The ear of maize, though not easily interpreted, is not 
difficult to describe. It is a spike upon whose thickened 
axis (the cob) naked grains (caryopses) are borne in lon- 
gitudinal or somewhat spiral rows; eight, ten, twelve or 
more in number. The number of rows is always even 
because the spikelets upon which the grains are borne are 
paired, a characteristic in which maize differs from its 
nearest relatives, teosinte and Tripsacum, whose spike- 
lets are solitary. Each rank of paired spikelets is clearly 
the equivalent of two rows of grain in the mature ear. 
The ear is enclosed in husks which are modified, over- 
lapping leaf-sheaths. The ear is obviously the terminal 
inflorescence of a lateral branch whose internodes have, 
probably during the course of domestication, become 
drastically contracted. 
Homology of Har and Tassel 
The general nature of the ear is sufficiently clear so 
that there can be little doubt that it is the homologue of 
the central spike* of the staminate inflorescence, the tas- 
sel. ‘This homology may have been vaguely suspected by 
some of the earlier students including Wigand, Ascher- 
*In one of his recent papers Weatherwax (19) calls this structure 
a “‘terminal raceme.’’ I prefer the older but equally appropriate 
**central spike.’’ 
[ 35 ] 
