Feb., 1922] SCHAFFNER — CONTROL OF THE SEXUAL STATE 
73 
has reported similar conditions. The staminate and carpellate areas are 
sometimes in definite spots, and when the transition Hne happens to pass 
through a flower one side is staminate and the other carpellate. The writer 
has published a detailed account of such cases elsewhere (6). 
As a general rule the carpellate plants are the larger. There is an im- 
portant difference in the longevity of the peduncle. The staminate pe- 
duncles die and dry up soon after blooming, while the fertilized carpellate 
peduncles, of course, remain in a vigorous condition until the fruit is matured. 
In the intermediate plants, there is every gradation of robustness and per- 
sistence, depending on the degree of carpellateness of the individual. Those 
that are largely staminate, though they may have several well-developed 
green fruits, soon wither, while those that have but a few staminate flowers 
remain green and erect. There is no essential difference in the vegetative 
characters of the staminate and carpellate individuals. Both one-leaved 
and two-leaved plants are either staminate or carpellate in about equal 
proportions. 
A statistical study of the plants in the field was made with the results 
shown in table i, all plants showing any evidence of monoeciousness being 
classed as intermediate. 
Table i. Arisaema triphyllum in the Field 
Carpellate Plants 
Intermediate Plants 
staminate Plants 
Habitat 
Number 
Percentage 
Number 
Percentage 
Number 
Percentage 
I. Rich beech forest 
26 + 
167 
13 + 
727 
60 + 
IL Open pastured wood. . . 
13 + 
40 
12 + 
227 
73 + 
III. Rich, moist mixed forest 
% 
23 + 
7 
17 + 
23 
59 + 
IV. Base of north-facing 
limestone cliff in 
ravine, rather dry. . . . 
16 
10 + 
15 
10 
119 
79 + 
V. Rich mixed forest con- 
taining black humus . 
61 
36 + 
38 
22 + 
67 
40 + 
Totals and averages for the 
1874 plants 
444 
23 + 
267 
14 + 
IT63 
62 + 
It will be seen by an inspection of the table that there is a large fluctua- 
tion in sex ratios for the different habitats. The staminate plants are 
always much in excess of either the carpellate or the intermediate individu- 
als, and with the exception of the wet black humus habitat considerably over 
50 percent of the total. The fourth habitat, representing a rather dry, 
poor soil, is in striking contrast to the fifth and shows how plants are affected 
by the ordinary field environments. The rich, wet soil has, in proportion, 
more than three times as many carpellate plants as the poor, dry soil, more 
than twice as many intermediates, and only half as many staminate in- 
dividuals. As is shown below, these extreme fluctuations are due to the 
direct control of the sexual state by environmental factors and not to a 
difference in death rate between the two sexes. 
