LINDSTROM, GENETICAL RESEARCH WITH MAIZE 337 
brachytic type described by Kempton (1920) is different from the 
others to some extent, especially in the size of the ears, which are 
larger and perfectly normal. 
. Crosses of any of the four dwarf types result in normal or tall plants 
in F, with a segregation in F, into talls, parental types of dwarfs and 
combinations of the two dwarfs in the double recessive. A complete de- 
scription of the cross dd An An An x DD an an is reported by Emerson 
(1921). 
Leaf characters. — The most striking variation in the leaves is the li- 
guleless condition (Emerson 1912). This recessive character is apparent 
in both the seedling and mature plant stages. It is an unusually dis- 
tinct type. A liguleless (/g) plant seems to be normal in all other res- 
pects. 
Other leaf characters that are recessive in inheritance are crinkly 
(cr) leaf, glossy leaf, rugose, slashed or cut leaf and a type in which the 
midrib is practically the only portion of the leaf that develops. The in- 
terrelations of these various leaf characters have not been completely 
determined. 
Zigzag culms. — According to Eyster (1920) this character becomes 
apparent when the plant comes into tassel. An abnormal growth of the 
tissue of the culm on the side of the internode above the leaf attach- 
ment causes this internode to arch away from the leaf sheath. As alter- 
nate internodes have the leaves attached at opposite sides the result is 
a more or less zigzag stem. This character is highly variable. Genetic 
tests indicate that it is a recessive type, due to the double recessive 
condition of duplicate dominant genes (z zg) for normal growth (Eyster 
1922). 
Tassel characters. — In addition to the abnormal tassels of the pod 
and ramosa types already described there are others worthy of note. 
Male sterile. — Plants of this type are distinguished from the normal 
type only in the staminate inflorescence. The spikelets of the male- 
sterile plant are sterile. No pollen forms in the anther sacs and this ge- 
ves a characteristic appearance to the tassel. The type is a simple Men- 
delian recessive (Eyster 1921). 
Tassel ear. — As described by Emerson (1920), this abnormal type 
can be considered as a wholly pistillate-flowered plant since in place of 
the staminate inflorescence (tassel) there is developed an ear-like 
structure, with silks, which may form mature grains. The plant shows 
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