WEATHERWAX: MORPHOLOGY OF FLOWERS OF ZEA Mays 141 
flower can be found in the embryonic stages of development, and 
usually all trace of its presence is lost except the extra pair of 
glumes on the posterior side of the kernel. These little stamens, 
however, indicate that it at one time might have functioned and 
give us another clue to some of the evolutionary changes that this 
interesting plant has gone through.”’ 
Contrary to this statement, I find, as previously described, 
that all traces of the aborted flower are not lost but are present 
in every female spikelet, at least in rudimentary form, at the time 
of fecundation (Fic. 9). Moreover, if three rudimentary stamens 
in the spikelets of one particular ear give a clue to evolutionary 
changes, a much better clue must be given by the development of 
a normal caryopsis from the lower flower of every female spikelet 
of Country Gentleman sweet corn (FIG. 14). 
The structure of the perfect flowers in pod corn, with reference 
to the order in which the four flowers of a pair of spikelets lost 
their staminate elements on becoming ear spikelets, has been 
worked out by Kempton (14, p. 10). He concludes that the first 
to change was the upper flower of the sessile spikelet, then the 
upper flower in the pedicelled spikelet, and then the other two 
flowers in the same order. Many evidences that I have observed 
in the tassel of pod corn are in accord with these conclusions, but 
an occasional spikelet with a functional ovule in the upper flower 
and the stamens of this one and both pistil and stamens of the 
lower flower aborted would lead to the belief that the entire lower 
flower may sometimes have become aborted without a previous 
loss of function by its stamens. In such spikelet, too, the lodicules 
of the lower flower are almost normal in appearance, while those 
of the upper flower are very much reduced in size. This indicates 
the beginning of the line of evolution that has left rudimentary 
lodicules in the aborted flower and entirely removed them from 
the upper flower of the ordinary female spikelet. Moreover, 
more weight must be attributed to evolutionary evidences from 
spikelets of the ear, which have passed through the process, than 
to those from tassel spikelets, which may or may not be giving 
indications that we are interpreting correctly. | 
The structure of the stamens of these tassel flowers p 
@ problem that cannot be solved from the standpoint of gross 
resents 
