lying spiral phyllotaxy which, as will be shown later, is 
characteristic of North American maize. 
If these elongated inflorescences of Guarany pod corn 
are a valid criterion (and there seems to be no good reason 
to doubt that they are since they do not appear to rep- 
resent a teratological condition), then the ear of maize is 
much less complex than has generally been supposed. It 
is nothing more than astrongly compacted spike in which 
pairs of spikelets are borne in varying number in whorls 
at the nodes of a simple non- or weakly-articulated ra- 
chis. This description, however, applies only to ears of 
the general type exemplified by the Guarany variety. A 
second type of ear apparently exists and is considered 
below. 
Crosses of Maize and Teosinte 
The hypothesis, already discussed, of a polystichous 
ear developing from a distichous spike through shorten- 
ing and twisting of the axis was based on observations 
which Collins (5) had made upon segregates from maize- 
teosinte hybrids. In his paper he showed photographs 
of spikes representing the various steps assumed to have 
been involved; the restoration of the aborted spikelet, 
the yoking of adjacent segments of the rachis, and finally 
the change from distichy to polystichy. His figures are 
not too convincing. Especially lacking are specimens 
showing the transition from independent to yoked rachis 
segments. Nevertheless his description is correct in its 
principal details. My own material, probably because I 
have had much larger populations than Collins to draw 
from, show the transition from the independent to the 
yoked condition much more clearly than did his (Plate 
XI, figs. A, B, C). In teosinte the joints of the rachis 
stand almost directly above or below one another to pro- 
duce a structure which Collins has aptly described as 
[ 55 
