March, 1922] NEWCOMBE — BEHAVIOR OF SENSITIVE STIGMAS II3 
closed, and 5 were open; of those receiving much flour, 4 were closed and 
3 were open. Seventeen hours after the flour was applied, of the 11 re- 
ceiving little flour, 5 were closed, 5 were wide open, and one was open 45°; 
of the 7 receiving much flour, 4 were closed, and 3 were open 90° to 200°. 
Sixteen stigmas of Tecoma radicans were given dry wheat flour, and 
closed, the blossoms being kept in the house, standing in water in beakers. 
The behavior of 7 of these stigmas was followed for 3 days. Six of them 
remained continuously closed, and one opened during the night, at some 
time within 12 hours of closing. Of 7 other stigmas, of the group of 
16, 6 remained closed and one opened during 4 hours, when observations 
were discontinued. The other 2 stigmas, one hour after receiving flour 
and closing, were open 60° and 90° respectively, but were fully closed two 
and one half hours after receiving the flour. 
That the presence of the flour had the effect of keeping the stigmas of 
Tecoma closed was demonstrated by the behavior of several controls used 
at the same time as some of the 16 stigmas whose behavior has just been 
followed. Five stigmas were caused to close without being given anything; 
all opened within an hour and remained open during the 6 hours of ob- 
servation. 
Mimulus glahratus var. Jamesii, it will be recalled, has a closed flower, 
and its stigmas do not remain closed after pollination. Flour was used on 
10 stigmas of this species, and the results showed that flour neither causes 
the stigmas to close, nor does it prolong the closure if one closes the stigmas 
at the time the flour is applied. 
From the foregoing results, the stigmas of Mimulus glahratus and of 
Torenia fournieri, as far as the evidence goes, seem to behave in about the 
same way when given flour as when given pollen. That is, neither pollen 
nor flour keeps the stigmas closed. The stigmas of Tecoma and of Catalpa 
are certainly affected by the flour in that a larger proportion remain closed 
if given flour than if given no flour; but the flour does not keep so many 
closed as does the pollen. The difference in behavior with pollen and with 
flour is especially marked 12 to 20 hours after the primary closing: with 
pollen, the stigmas are likely to remain closed; but with flour the stigmas 
generally open finally. 
Starch. Wheat flour was heated to 80° in tap water to destroy the 
enzyme. It was then washed 3 times to remove the protein. The starch 
obtained was dried and applied to the stigmas of 9 flow^ers of the Catalpa. 
The preparation was kept in the house. After 3 hours 4 were open, 4 were 
closed, and one was open 30°. Twelve hours after applying the starch, 
all stigmas were open. Twelve other stigmas were given dry starch and 
all stigmas were stimulated to close. This preparation also was made in 
the house. After one hour, 11 stigmas were open, the other closed. This 
condition continued for 5 hours at least, and the next observation was made 
the next morning, 17 hours after the starch was applied. All 12 stigmas 
