Feb., 1922] SCHAFFNER CONTROL OF THE SEXUAL STATE 
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condition being complete in all except one individual which had three 
staminate flowers at the tip of the inflorescence. 
Of the 5 plants which were originally intermediate or monoecious, 
and which had been changed to the pure staminate condition the previous 
season, 4 were pure carpellate and one which had given off a large branch the 
first year and whose corm was thus reduced gave rise to 2 staminate shoots. 
Of the 25 plants which were originally pure carpellate, and of which 23 
had been caused to change their sexual state the previous season, one failed 
to bloom, one was pure staminate, one was intermediate with a carpellate in- 
florescence showing a single staminate flower at the top, and 22 were pure 
carpellate, having reversed their sexual state back to the condition they 
were in when originally transplanted. 
The corms have given off a considerable number of small buds, so it is 
probable that future reversals will not be so nearly universal as in the first 
two seasons. The twin plant of the previous season had separated its 
corms completely, and both the twins that had been completely staminate 
the previous season were now completely carpellate. 
The experiments show conclusively that it is possible to exercise almost 
complete control over the sexual state of Arisaema triphyllum. A slight 
disturbing factor is introduced because of the fact that the corms often pro- 
duce buds of a sufficient size to rob the parent of much of its food supply. 
Sex reversal is complete in the individual in either direction from time to 
time, the male to the female or vice versa, or the reversal may be partial, 
from a pure male or female state to a hermaphroditic condition, or vice versa 
from a hermaphroditic condition to a pure male or female state. The exact 
factor which induces the reversal has not been ascertained. The writer was 
desirous to show first of all that sex reversal actually takes place in many 
plants. Apparently in Arisaema triphyllum the sexual state depends mainly 
on the water supply, or on the nutrition, or on both combined. According to 
Atkinson's (i) experiments the determining factor might be the varying 
amounts of the nutriment in the corm. Pickett (3) believes his field ob- 
servations and experiments show that ''the amount of water available at a 
certain period in development is directly or indirectly responsible" for the 
given sexual state. Apparently the sexual state may be determined in a 
feeble or in an intense manner. If the female state is of low degree, the 
inflorescence may change from carpellate below to staminate toward the 
top, or in some cases any patch of cells may change to- the male state what- 
ever their position in the spadix. If the sexual state is originally deter- 
mined in the bud as male, the reversal usually takes place in patches at the 
sides of the spadix, involving one or more flowers, apparently without 
any relation to the age of the cells or to their position on the inflorescence 
axis. 
Arisaema triphyllum is an unusually favorable perennial herb for ex- 
perimental purposes in studies on sex control and reversal, and there should 
