transition from a vegetative shoot to a reproductive one 
rather than the usual abrupt change (Galinat, 1954b). 
Spikelets may be converted into ‘‘tassel-plantlets’’ as an 
“‘after-effect,’’ resulting from an insufficient number of 
short-days during the early floral development of short- 
day maize (Galinat and Naylor, 1951). The growing 
point of the spikelet-axis or rachilla may shift from 
‘‘cutting-off’’ floret primordia to that of initiating spike- 
lets as this axis becomes the rachis of an ear enclosed by 
husks modified from glumes and lemmas (Weatherwax, 
1925). Finally, during the evolution of the maize ear, 
either a tassel branch or a spikelet from the tassel seems 
to have been modified as a tiny, sub-tassel ear which later 
descended to a more efficient position on the stalk, where 
it could increase in size (Mangelsdorf, 1958). 
Prophylls. The prophyll-part of the phytomer is a 
two-keeled, leaf-like organ which develops at or near the 
axil of a lateral bud. Its two-keeled form may result 
from its being pressed between the branch axis and parent 
axis during early development (Arber, 1934). Pressure 
between binding leaf-sheaths and their expanding axil- 
lary buds and associated prophylls is known to be respon- 
sible for the initiation of permanent grooves in the inter- 
node of the parent axis, and, in some bamboos, this 
channel retains the imprint of the prophyll, even after it 
has been left behind by the elongation of the internode 
(Arber, 1934). It is apparent that the prophyll occupies 
the most crowded position in the phytomer, especially 
along the rachis, where it is either absent or highly modi- 
fied and reduced. But when the position of the floral 
prophyll is moved away from the rachis to a less crowded 
position in the ultimate branches (florets), it then devel- 
ops fully as the so-called ‘‘palea.’’ 
The problem then is to identify the anatomical remains 
of the prophyll at or near the axil of a branch within the 
Le 
