off on one side (Figs. 7-9). Various twisted configura- 
tions may distort the spathe, rachis, and peduncle as the 
branch tends to become opposite rather than adjacent to 
its associated spathe (Figs. 10-138). If the axillary branch 
develops to one side of, or on the opposite side of, the 
node at which a terminal leaf would normally be ex- 
pected, then both spathe-leaf and branch may achieve 
optimum development (Fig. 14). Two leaves, or a leat 
and a sheath (husk), may be borne at this node. Such a 
pair of leaves (Figs. 15, 17) may have a common origin 
(Figs. 7-9), although distortion of the node may cause 
them to appear as being separated by a short and twisted 
internode (Fig. 13). In extreme cases of spathe develop- 
ment, a single spikelet or the tassel branch as a whole 
may be modified to form a small shank terminated by a 
small ear (Figs. 15-17). The morphological change from 
either a spikelet or tassel branch to a many-ranked ear 
involves a change from bilateral to radial symmetry. 
Such a transformation is common in maize. Depauperate 
ears frequently exhibit reductions from a radial to a bi- 
lateral condition. One might expect that, if there were 
a reduction during evolution of a leaf terminal to the 
culm, then there might also be a corresponding reduc- 
tion of its axillary ear to a bilateral tassel branch. 
Archaeological remains have been found which sug- 
gest that sub-tassel ear development may have been char- 
acteristic of primitive maize (Mangelsdorf, 1954 and 
unpub. ). This evidence, so far as it goes, indicates that 
the tassel of wild maize was unbranched or sparsely 
branched and bore a few pistillate spikelets basally. The 
spathe subtending the tassel may have had a protective 
function for these pistillate spikelets during the prepolli- 
nation period. Subsequent to pollination, rapid elonga- 
tion above the sub-tassel node might elevate the mature 
grain for dispersal. Mangelsdorf has suggested (unpub. ) 
C gee 4 
2 O35 
