and Muchlaena ought to be made conspecific, an idea 
which we had earlier (87) considered but rejected, giving 
our reasons for doing so. Darlington does not seem to 
be aware of our publication. Sinnott, Dunn, and Dob- 
zhansky (46) refer to annual teosinte as Zea mexicana 
without reservation. In view of the above facts, Weath- 
erwax’s (58) statement that our ‘‘proposal has met with 
little favor’’ is somewhat erroneous to say the least. 
The actual issue involved is whether or not natural re- 
lationships as indicated by cytogenetical behavior and 
gene exchange without the use of artificial techniques are 
to be recognized in taxonomic treatments. If they are 
to be recognized, there can be no doubt that the consoli- 
dation of Zea and Huchlaena is justified. 
SUMMARY 
The circumstantial evidence that teosinte originated 
as a hybrid between corn and Tripsacum is substantially 
stronger now than in 1939, when the idea was first pro- 
posed, for the following reasons: Not only has the cross 
between corn and Tripsacum been successfully repeated, 
but it has been made without special techniques. ‘The 
species of Tripsacum (7°. dactyloides) which has come 
nearest to showing introgression with corn under experi- 
mental control has been reported in Guatemala, where 
teosinte is believed to have originated and where corn is 
known to have been abundant since ancient times. There 
is increasing evidence, also, that 7° dactyloides or forms 
similar to it, previously were more common in the area 
than they are now. 
Tripsacum genes have been demonstrated to have a 
phenotypic effect in corn-Tripsacum hybrids, a natural 
supposition which was once doubted by some students 
of this problem. The first report of crossing over between 
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