TasLe |. A comparison of some of the important botanical characteristics which 
distinguish Manisuris, Tripsacum and Zea. 
pt pd pet — 
Wn Re 
a 
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17. 
in Plate XLVI. The dominance of monoecism might 
be expected, since this evolved trait is dominant within 
maize itself to certain recessive mutations, ‘‘anther ear”’ 
and ‘‘dwarf-1°’ which, among their effects, cause develop- 
ment of perfect flowers. Although monoecism occurs also 
in the Oriental Maydeae, these grasses can be ruled out 
as putative parents of Tripsacum because they are lack- 
ing in other essential characteristics, such as the thick- 
ened rachis with cupule development found in maize. 
Long styles and large pollen could be derived better 
from maize than from any other known grass, although 
the wild maize which we are considering as a parent of 
Tripsacum probably had shorter styles and smaller pollen 
than any living race of maize, if the small size of archaeo- 
SCWOMNAUOLWNH eS 
Characteristic Manisuris Tripsacum Zea 
. Perfect flower vs monoecious perfect flowers monoecious monoecious 
. Length of styles short intermediate long 
. Styles, bifurcation separate basal fusion fused 
. Styles, hairs profuse intermediate sparse 
. Size of anthers small intermediate large 
. Size of pollen small intermediate large 
. Size of rachis slender intermediate thick 
Cupules in rachis absent present present 
. Rachis abscission present present absent 
. Rachilla to rachis parallel parallel (pistillate) right angles 
(pistillate ) 
. Glume texture indurated indurated herbaceous! 
. Glume surface smooth? or sculptured smooth smooth 
. Spikelets binate 1 fertile, 1 sterile staminate staminate & 
pistillate 
. Phyllotaxy distichous distichous polystichous 
. Leaf width narrow intermediate broad 
. Height of tillers relative tall 3 intermediate 3 short 
to main stalk 
Growth habit perennial perennial annual 
Root stocks present present absent 
18. 
1 Herbaceous or nearly so in archaeological wild maize. 
2 Smooth first glumes in M. aurita. The other New World species are sculptured. 
3 On two year old plants. 
[ 294 | 
