frequent and pronounced in varieties from) Bolivia and 
Peru. This feature is enhanced by tassel proliferation 
resulting from unfavorable photoperiods during floral 
differentiation of short-day maize and is also character- 
istic of tunicate, corn-grass and teopod maize. ‘Tassels 
which were proliferated or associated with any of the 
above variants were excluded from this study. 
Specimens of Trvpsacum and Muchlaena trom the Keo- 
nomic Herbarium of Oakes Ames were examined in an 
attempt to determine if this rudimentary spathe might 
be derived from introgression with these near relatives 
of maize. It was found that in Tripsacum pilosum, T. 
lanceolatum, T. dactyloides and TY fasciculatum there is 
a small ridge encircling the base of the inflorescence. In 
these species, with 7. dactyloides as a possible exception, 
the ridge is more in the nature of a fracture line for the 
lowermost rachis-fruit case than that of a vestigial leaf. 
In Muchlaena mevicana there is often a small leaf-like 
protrusion subtending the lowermost tassel branch. This 
structure is probably a vestigial spathe since its homo- 
logue subtending a lateral pistillate spike is a well- 
developed spathe. The degree of development of the 
spathe subtending the tassel of duchlaena appears to be, 
on the average, intermediate between that of Tripsacum 
and that of maize. 
In modern maize, partial development of the sub- 
tassel spathe and its axillary branch is usually associated 
with various anomalies. Both the spathe and its axillary 
peduncle may be adnate to the rachis. The peduncle 
may adhere to the rachis over a greater distance than its 
subtending spathe (Figs. 1-3). The auricles of the spathe 
may be greatly elongated on cither side of a reduced 
blade (Figs. 4-6). Development of the spathe may be 
unilateral in relation to the branch, so that it appears as 
if its blade had been cleaved down the midrib and torn 
[ 262 ] 
