June xi, 19 x 7 
Hybrids of Zea ramosa and Zea tunicata 
385 
like the Andalusian fowls. Our experiments have contained tunicate 
strains from three distinct sources; but, since other workers report the 
existence of pure-tunicate strains, it may be that still other stocks be- 
have differently. 
The distinction between full tunicate and half tunicate has not always 
been made in our pedigrees, but the records show 17 progenies where the 
number of full-tunicate plants is recorded. The total number of plants 
in these 17 progenies is 187, of which 46 were classed as full tunicate. 
If, as suggested, the full-tunicate plants are the homozygous form, the 
expected for the number of individuals involved would be 62, a devia¬ 
tion of 16, or four times the probable error, a rather large deviation to 
be ascribed to chance, but not sufficiently aberrant to offset the failure 
to secure homozygous individuals among the half-tunicate plants. The 
distinction between full and half tunicate is not always easy to make, and 
it would appear from the ratios that we have been referring some of the 
less pronounced examples of the full tunicate to the half-tunicate class. 
By concentrating selection on this group of plants, more or less inter¬ 
mediate between full and half tunicate, it may be possible to secure a 
homozygous strain. But in the stocks with which we have been ex¬ 
perimenting, individuals of the type shown in Plate 13, A, or that shown 
by East and Hayes (1911) would not serve as examples of pure-tunicate 
maize. 
The class with bisexual terminal inflorescence, which is here assumed 
to be homozygous, will be referred to as “full tunicate" and the ordinary 
tunicate type, which we look 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. 
Z. ramosa , or branched maize, is a variation from ordinary maize dis¬ 
covered by Dr. W. B. Gemert (1912) at the Illinois Agricultural Experi¬ 
ment Station. The original ear was found in 1909 in a field of Learning 
com. 
Z. ramosa differs from the normal maize in having the pistillate 
inflorescence, or ear, which is normally simple, replaced by a compound 
inflorescence branched like the tassel (PI. 14, A, c). There is also a 
less striking but equally significant change in the branching of the 
tassel (PI. 16). 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 main axis of the inflorescence. 
Thus, in passing from the base to the tip of the tassel, there is an abrupt 
transition from the uppermost branch to simple pairs of spikelets. In 
the Z. ramosa tassel the branches are much more numerous and gradu¬ 
ally decrease in size from the base upward, the transition from branches 
to pairs of spikelets being imperceptibly gradual. 
