March, 1922] NEWCOMBE BEHAVIOR OF SENSITIVE STIGMAS 
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nearly saturated with moisture for 26 hours, at 23°. In this period none of 
the stigmas closed. Pollen germination as high as 75 percent was shown on 
all stigmas. Of the 48 stigmas mentioned above as cross-poUinated and 
kept in a moderately moist chamber, 26 closed or partially closed 3 to 10 
hours after pollination, but not one of them remained closed continuously 
for the 24 hours or more of the experiment. All of these stigmas showed 
pollen germination estimated in the different individuals at from 10 percent 
to 75 percent, the percentage of germination varying with the degree of 
closure or with the duration of the closure of the stigmas. 
The stigmas of Torenia fournieri proved themselves less influenced by 
dryness of air than did those of Catalpa. When a potted plant bearing 
blossoms was kept in moderately moist air, pollinated stigmas generally 
remained open if the pollination was so done as to avoid primary closing, 
or the stigmas opened in 30 to 60 minutes if they had been stimulated to 
close at the time of pollination. In three series of tests in which some of 
the stigmas had closed and so remained, while others had opened or re- 
mained open, microscopic examination at the end of 24 hours showed the 
pollen ungerminated on the open stigmas, but germinated on the closed 
ones. A more extensive series of tests was made with this same species 
in which the growth of ovules was used as the criterion for the growth of 
pollen on the stigma. In one series, during damp weather, 13 stigmas 
were given pollen without causing closing, the plant being kept outdoors 
under a net screen in natural atmosphere. The stigmas did not close, and 
there was no fertihzation. In another test, six flowers had pollen placed 
on their stigmas without closing. The pot was kept on wet ground out- 
doors under a net-covered wire cage covered with a wet blanket nights, 
and with water falling on the net during the day. The plant must have 
been in a nearly moisture-saturated atmosphere continuously, though no 
water fell on the plant. The preparation was kept going for six days without 
closing of stigmas. At the end of this period, all six ovaries showed abun- 
dant, large ovules. 
A similar test to the foregoing, except that the chamber holding the 
plant was kept only moderately moist, was made with six pollinated flowers. 
Of these, four stigmas closed 4^^ to 14 hours after pollination, remained 
closed 12 to 14 hours, opened or partly opened for the next 3 to 10 hours, 
then closed permanently. The ovaries of these four showed good growth 
with a good supply of ovules eight days after pollination. The other two 
stigmas half closed about 12 hours after pollination and so remained be- 
tween 7 and 10 hours, then opened and so remained. The ovaries of these 
two flowers after 8 days had grown but little and contained but a few en- 
larged ovules. The pollen used on the foregoing six stigmas was all taken 
from the longer pair of stamens of one flower. The flowers were constantly 
protected from insects by a cheesecloth net. 
Nine flowers of Tecoma radicans were brought into the laboratory where 
