EFFECT OF ENVIRONMENTAL CONDITIONS UPON TOBACCO PLANTS 499 
Unfavorable conditions reduce the size of the inflorescence quite 
as readily as the size of the leaves. In severely stunted plants the 
branches of the terminal whorl become so greatly reduced that they may 
be represented by single blossoms as was the case with many plants 
grown in the 4-inch pots in the second experiment. (See Plate 
XX.) 
In plants stunted even more severely than those in the 4-inch pots 
in the second experiment, the terminal whorl is completely suppressed, 
and the inflorescence of the plant is reduced to the single terminal 
blossom of the main stem. Such plants were only 8 to 10 inches in 
height when blossoming finally took place, and the majority of the 
leaves were reduced to mere bracts. 
Experiments have shown that tobacco plants may be very con- 
siderably stunted before any retardation in time of blossoming takes 
place. Beyond these limits, however, blossoming in severely stunted 
plants may be delayed almost indefinitely. In fact, in the writer's 
experience, it has been possible to keep young tobacco plants in a 
practically dormant condition for periods as long as the normal life 
of the plant. Plants kept in a practically dormant condition for about 
5 months are shown in Plates XXI-XXIII. The smallest plants 
in the 2-inch pots are sister plants of the same age as the large plants, 
and all were grown from seed sowed Nov. 13, 1912. Experiments 
with these dormant plants have shown that this inhibition of growth 
is only temporary in its effects. If such plants are transplanted to the 
field, vigorous growth ensues and plants of nearly normal size are 
produced. 
In the field it is known that the number of commercial leaves is 
more or less variable from year to year. These variations depend 
upon such accidental factors as depth of transplanting, drought, height 
of topping, etc., and do not show the true number of leaves produced 
by the plants. In ordinary field practice probably not less than 6 or 8 
leaves above the cotyledons are lost. As shown in Table II, the 
plants grown in the 8-inch pots lost from 8 to 10 leaves above the 
cotyledons, while those more severely stunted in the 4-inch pots lost 
in some instances as many as 17 leaves. 
From the writer's experimental data in Tables I and II it is indicated 
that the number of nodes below the terminal bud is not changed by 
environmental conditions. 
