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the same varieties to-day. In view of these facts, it may 
be proper to offer the results of experimental experience 
uponthe permanency of varieties. 
Varieties of the same general character cross-breed very 
readily, and this also seems to be the case as between vari- 
-eties of the same tribe within a race, and between. varieties 
occupying like positions of classification in different races. 
Purity of seed, however, may offer a prepotency which 
shall reject outcrosses, so long as the variety pollen is pres- 
ent insufficient abundance. One illustration of this propo- 
sition may be allowed. The Waushakum Flint Corn isa 
pure bred variety of marked uniformity. This variety in 
1882 was grown alongside ten other varieties: the resultant 
‘seed was planted in 1883 amid 128 other sorts: the resultant 
‘seed In 1884 was again planted amidst 135 other sorts. In 
1885 the crop was perfectly on type, and neither in this 
year nor in the preceding years were any effects of cross- 
fertilization apparent. 
The mass of the evidence gained by experimental trials, 
justifies the proposition that there is a resistance to cross- 
fertilization as between the tribes. Repeated plantings of 
the tribes I, II, and III together have given no cross-breds, 
and no variations, with but a few obscure exceptions. 
These exceptions probably came from the exclusion of its 
own pollen, whereby a forced cross was admitted. This 
matter will be referred to later on in treating of * species 
crosses. | 
_ Alike resistance to crosses has also been observed as 
between the races. Corn of the different races grown 
together have not given from their planted resultant crop, 
any evidence that can lead to any other inference save that 
in the presence of their own pollen, other race pollen has 
been rejected. 
_ In respect to the * species, we find that from current hy- 
bridization, one species can pass to another, but not uni- 
formly in both directions. Thus the flint kernel may appear 
on the sweet ear, but the sweet kernel does not readily pass 
‘to the flint; but in all these cases the crossing only takes 
place between like races of the two species. \Ve have ob- 
served few, if any indisputable instances of the flint and 
‘dent, or sweet and dent kernels appearing together on the 
same ear from plants of our own growing, but a few cases 
‘of such crossings have been noted in collected ears, of 
whose history we have no knowledge. The seed planted 
from currently hybridized samples, show that hybridiza- 
tion has taken place between the * species, for the crop is 
not uniformly of a kind. The tendency is, however, very 
strongly towards the production of the parentage, without 
intermediates; so much so that it is doubtful if intermediates 
