1912] HASSELBRING—CUBAN TOBACCO I2I 
in their work with wheat, showed that this influence of the environ- 
ment is exerted also on the chemical composition of plants. When 
wheat of one variety from one locality was grown in other localities, 
with a widely different environment, the chemical composition 
of the grain was different in each locality. These differences per- 
sisted as long as the wheat was grown in the particular locality, but 
if at any time seed from one locality was grown in any of the 
others, the grain took on the composition of the wheat constantly 
grown in those localities. The tobacco plant is extremely suscep- 
tible to changes in the environment, but such changes affect all the 
plants of a pure strain alike, and do not cause a breaking up of the 
type. Among the plants grown in Michigan, some of the types 
showed a different shade of green from that shown by the same 
types in Cuba, but all the plants changed alike. 
Description of the types 
The taxonomy of the TaBacum section of the genus Nicotiana is 
endlessly confused, and it is not possible from the materials at hand 
to give a proper classification of the forms involved in these studies. 
Many of them are undoubtedly well defined species. The facts 
that they have maintained themselves for a long period of time, 
that no effort has been made to improve them, and that they 
resemble races from Mexico, seem to indicate that these forms are 
not far removed from the original wild species of tobacco. As their 
definite classification would require the study of vastly more 
material than is at my disposal, it seems best to indicate the general 
relationships of the types and give the main characteristics by 
which they were distinguished. For similar reasons, it is useless 
to speculate on the origin of the forms of tobacco which now occur 
in Cuba. Many of the growers have a vague idea that the tobacco 
of today is not the real Cuban tobacco famous in former times. It 
is a common belief among them that during the long wars tobacco 
growing was almost exterminated on the island, and that subse- 
quently tobacco was imported from Mexico, Porto Rico, and other 
regions. It is more probable, however, that even in early times 
the tobacco of Cuba consisted of a mixture of forms. As early as 
