cences of maize. To say that the many-ranked ear of 
maize departs from its two-ranked prototype by virtue 
of its more complex phyllotaxy is scarcely more explana- 
tory than to say that the former has more numerous ranks 
than the latter. Nevertheless phyllotaxy, as will become 
apparent later, is immensely important. 
Actually, as Reeves (15) points out, the polystichous 
inflorescence is sufficiently common in various genera of 
grasses so that no special explanation of its occurrence in 
maize is required. Its origin is a problem of the Gramin- 
eae as a group rather than of maize alone. The unique- 
ness of maize lies not so much in its polystichous ear as 
in the fact that its staminate inflorescence is usually a 
modified panicle while its pistillate inflorescence is usu- 
ally a spike. Collins’ hypothesis furnishes a very satis- 
factory explanation of the steps involved in the trans- 
formation of one to the other. 
Anderson’s (1) observations, previously mentioned, 
that the characteristics of the ear are correlated with 
characteristics of the lateral branches of the tassel, may 
be interpreted to mean, not that the ear is the product 
of fusion and that the lateral branches are homologues of 
its component parts, but simply that the lateral branches 
are capable of revealing what kind of panicle it is that 
has become modified to produce the ear. 
Twisting of a [Two-Ranked Spike. The third 
hypothesis, that the polystichous maize ear arose through 
the shortening and twisting of a two-ranked spike, such 
as the spike of teosinte, was also formulated by Collins 
(5). This hypothesis grew out of observations made by 
him on the pistillate spikes of an Fg population of a 
maize-teosinte hybrid from which a series of specimens 
could be selected to illustrate the steps involved in chang- 
ing a structure like the spike of teosinte to one resem- 
[ 43 ] 
