346 
GENETICS: G. N. COLLINS 
The ratios in which the different classes occur indicate that the class 
with the bisexual terminal inflorescence is the homozygous form, and 
that the ordinary tunicate plants represent the heterozygous form, a 
cross between the form with the bisexual inflorescence and the normal 
non- tunicate maize. 
From experiments involving forty-three progenies derived from three 
distinct sources, it would appear that the ordinary type of tunicate 
ear represents an example of imperfect dominance as unfixable as the 
Andalusian fowls, but since other workers report the existence of pure 
tunicate strains it may be that other stocks behave differently. 
The class with bisexual terminal inflorescence, which is here consid- 
ered homozygous, will be referred to as full-tunicate and the ordinary 
tunicate type, which is looked upon as heterozygous, will be termed 
half -tunicate. The term tunicate or podded will be used as a general 
term including both of the above classes. 
Zea ramosa or branched maize, discovered by Dr. W. B. Gernert^ at 
the IlHnois Agricultural Experiment Station, differs from normal maize 
in having the pistillate inflorescence or ear which is normally simple 
replaced by a compound inflorescence. There is also a less striking 
but equally significant change in the branching of the terminal inflo- 
rescence or tassel. In normal maize the terminal inflorescence bears a 
number of branches at its base. Above the uppermost branch the 
axis is continued into what is termed the central spike where the pairs 
of spikelets are borne directly on the axis of the inflorescence. There 
is thus in passing from the base to the tip of the tassel an abrupt transi- 
tion from the uppermost branch to simple pairs of spikelets. In the 
Zea ramosa tassel the branches are much more numerous and grad- 
ually decrease in size from the base upward, the transition from branches 
to pairs of spikelets being imperceptibly gradual. 
Unlike Zea tunicata, Zea ramosa is a recessive variation. The dom- 
inance of normal maize over this variation seems complete. It has not 
been possible in any way to distinguish between plants heterozygous 
for the ramosa character and normal maize. So far as observed, the 
character behaves as a simple Mendelian unit. 
Both Zea ramosa and Zea tunicata are variations from normal maize 
toward the general type of grasses, and as such may be looked upon as 
reversions, since both cases involve a loss of a speciaHzation that dis- 
tinguishes maize from practically all other grasses. 
Description of the Hybrid. — The cross between Zea tunicata and Zea 
ramosa was made in 1914. Nine first-generation plants of this cross 
were grown in 1915. Of these four were tunicate, and five normal, 
