WEATHERWAX: SPIKELETS OF ZEA Mays 485 
lodicules. It will be shown that the present maize spikelet, 
whether male or female, has: essentially the structure of this 
primitive one with some of its parts suppressed. 
The spikelet primordium makes its appearance as a rounded 
protuberance on the rachis. The first differentiation to appear is 
in the formation of the lower glume, and it is soon followed by the 
upper one (G, TEXT-FIGS. I, 6, 7). The two lemmae arise almost 
simultaneously with the appearance of the stamens of the upper 
flower (L and S, TEXT-FIGS. 2, 3, 8). From the lower side of the 
undifferentiated part of the spikelet now appears the primordium 
of the lower flower (F, TEXT-FIGS. 3, 4, 8), and the palea 
of the upper flower soon follows (P, TExt-Fic. 9). ‘The 
palea of the lower flower appears much later (P, TEXT-FIGs. 
5,10). The older flower seems to be terminal and the younger one 
lateral on the rachilla, but it is probably better to consider both 
flowers lateral branches of this axis, which terminates between the | 
two paleae. This point, however, should be investigated further. 
In the development of the flower from its primordium the 
-stamens are first differentiated; these are followed by the lodicules 
and the part that is left is the primordium of the pistil. 
Up to the time of the differentiation of the primordia of the 
stamen and the pistil, the male and female spikelets have looked 
very much alike; but now, accompanying the sexual differentiation, 
there begins a divergence in the appearance of the two. The cov- 
ering of husks for the female inflorescence, the effects of crowding, 
etc., bring about further changes until the male and female spike- 
lets finally resemble each other so little that there is a current 
doubt, or ignorance, at least, of their homologies. 
In both flowers of the male spikelet the stamens and lodicules 
are fully developed, but the development of the pistils is soon’ 
arrested, and they disorganize. 
The lodicules begin as small protuberances and develop into 
thick, short, truncated bodies. They are well supplied with vas- 
cular tissue and at anthesis are quickly distended to two or three 
times their former width, very efficiently holding open the spikelet 
while the filaments of the stamens are elongating.. The develop- 
ment of the stamen does not differ very much from that in other 
grasses. Cross sections of anthers just before the time of the : 
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