348 
GENETICS: G. N. COLLINS 
NUMBER EX- 
PECTED OUT OF 
EACH 16 
GAMETIC COMPOSITION 
CHARACTERS OF PLANT 
EXPECTED 
NUMBERS 
OBSERVED 
NUMBER 
1 
2 
2 
4 
2 
1 
2 
1 
T'T'R R 
T'T'R R' 
T T'R R 
T T' R R' 
T T R R 
T T'R R' 
T T R'R' 
T T' R' R' 
T' T' R' R' 
Normal \ 
Normal / 
Half-tunicate \ 
Half-tunicate / 
Full-tunicate 1 
Full-tunicate / 
Tunicate ramosa \ 
Tunicate ramosa / 
Ramosa 
61.2 
122.0 
61.2 
61.2 
20.4 
64 
121 
61 
64 
16 
Total 
326.0 
326.0 
In each of the parent varieties there is a deviation from normal 
maize in both the staminate and pistillate inflorescences. It is of in- 
terest, therefore, to determine so far as possible whether the changes 
in the two parts of the plant are due to a single gametic change, or 
whether they may be inherited separately. 
With this point in mind the plants were classified with respect to 
their tassels, and ears, independently, with the following results: 
The normal plants were all normal in both tassel and ear. 
The distinction between half- and full-tunicate is somewhat arbi- 
trary, but with one exception all the 121 plants classified as half -tunicate 
by their tassels also had ears classed as half -tunicate. That the dis- 
tinction is genetic and not merely physiological is indicated by the ab- 
sence of any sensible correlation between the length of the staminate 
and pistillate glumes on the individuals inside the half -tunicate group. 
Of the 53 plants classed as full-tunicate by their tassels, all but two 
had either full-tunicate ears, or none at all, and the two exceptions had 
pistillate glumes only sKghtly below 45 mm., the minimum length set 
for the glumes of full-tunicate ears. There is then almost a perfect 
correlation between the type of tassel and ear, but here again there is 
no correlation inside the group. That is, long glumes in the tassel 
were not correlated with long glumes on the ear. Even the extreme 
form of full-tunicate plants that produced no ears did not differ, with re- 
spect to the length of the staminate glumes, from the plants bearing ears. 
When both tunicate and ramosa characters were present in the ears, 
the tassels were always ramosa but the tunicate characters were not 
always apparent in the tassel. 
Conversely, the 53 plants with ramosa tassels all exhibited ramosa 
characters in the ears, either pure or combined with the tunicate 
character. 
Perhaps the most interesting class of plants were those with cauli- 
