112 
AMERICAN JOURNAL OF BOTANY 
[Vol. 9, 
after the primary closing, or induces a secondary closing if there has been 
a secondary opening or if there has been no primary closing. It should 
be recalled here that the two species Utricularia vulgaris and Mimulus 
glahratus var. Jamesii are exceptional in that the stigmas show no secondary 
closing. It may also be recalled that the other species reported in this 
paper show much oftener than hitherto supposed both secondary opening 
and a failure of secondary closing, especially in moist air. 
Moist and dry pollen. Only 19 stigmas were used — 7 of Torenia fournieri 
and 12 of Catalpa — in comparing the effect of moist and of dry pollen on 
maintaining the closed condition of stigmas. The result cannot be said 
to be conclusive, but only indicative. When the atmosphere was dry, 
the stigmas receiving dry pollen remained closed longer than those receiving 
moist pollen, or a larger proportion of the former remained permanently 
closed. When the atmosphere was moist, the most of the stigmas opened 
without distinction between dry and moist pollen. The dry and moist 
pollens were always used at the same time on similar flowers, the dry being 
taken in some cases from anthers open 24 or more hours, while the moist 
was taken from unopened anthers. Or, in other cases, both pollens were 
taken from the same anthers, open 24 or more hours, the pollen applied 
dry to some anthers and moistened with spring water before being applied 
to others. 
Wheat flour. Four open stigmas of Torenia were given a fair amount 
of wheat flour, and closed. The plant bearing the flowers was kept in the 
house where the moisture was considerable. All stigmas began opening 
in 30 minutes. In 90 minutes, all were fully open. 
Ten stigmas of Catalpa, while the flowers were still on the tree, were 
covered with wheat flour and made to close. The temperature was 27°, 
and the air fairly moist, but the sky clear. Cheesecloth bags were drawn 
over the panicles. After 3 hours, 5 stigmas were still closed, and the other 
5 were open slightly from the tips of the lobes to their insertion. The next 
observation was made the next morning, 18 hours after the stigmas were 
closed; all but one stigma were open. Three stigmas, as controls, were 
closed but given no flour at the same time as the last 10, and were otherwise 
given the same treatment. All three were wide open when observed two 
and three fourths hours after closing, and still open 18 hours after closing. 
Eighteen flowers of Catalpa were plucked, placed in a damp chamber and 
brought into the house, where the temperature was the same as outdoors, 
23°; there had been showers, and the air was fairly moist. Eleven stigmas 
were given a thin coating of wheat flour, and 7 stigmas a heavy coating, and 
all stigmas were closed in the act of applying the flour. After 150 minutes, 
7 were closed, 2 were open, and 2 were one third open of those receiving but 
a thin cover of flour Of the 7 stigmas receiving a thick cover of flour, 
4 were closed and 3 were open 30°, 150 minutes after the first closing. 
Six houis after the flour was applied, of the 11 receiving little flour, 6 were 
