no 
AMERICAN JOURNAL OF BOTANY 
[Vol. 9. 
the behavior in Mimulus was not followed long enough to determine this 
matter. Yet it cannot be doubted that the pollen germinates on the open 
stigmas of the Mimulus and that fertilization results. Pollen germination 
on the open stigma of Utricularia was determined by teasing out several 
stigmas some hours after pollination. Besides the seven cases, specially 
tested as noted above, many other stigmas of Utricularia were seen to have 
the lower lip recurved (open) after the fall of the corolla. Yet all these 
flowers bore seeds. 
The other species subjected to experiment and observation have open 
flowers and hence do not keep moisture about their stigmas sufficient, in 
usual weather, to promote germination. It would, perhaps, be correct to 
say that they do not keep sufficient moisture about their stigmas to allow, 
or cause, reopening after the primary closing, or to prevent the secondary 
closing in case there has been a secondary opening. Especially careful 
observations for determining these relations have been made with Torenia 
fournieri and Catalpa hignonioides . The general result has been the failure 
of secondary closing in very moist air and the occurrence of secondary 
closing in dry air. Six stigmas of Torenia, pollinated and not closed, kept 
outdoors under a fine net, weather 23° to 26°, not very moist, all closed in 
to 14 hours. Six other stigmas, pollinated and not closed, the plant 
kept day and night outdoors in a nearly moisture-saturated chamber, in 
good light by day, temperature 23° to 26°, did not close at all. Seven 
other stigmas were cross-pollinated and closed at 11 A.M. on a sunny 
summer's day, and the potted plants were set outdoors in the sun under a 
fine net. Four of the stigmas soon opened at the tips of the lobes, but 
closed again during the next few hours. At 7:50 P.M. six of the seven were 
well closed, and the seventh was half closed. The plants were then brought 
into the house and kept in moister air over night. In the morning, four 
stigmas were open, the other three closed. The stigmas of thirteen flowers 
had small masses of pollen placed on the stigmatic surface near the tips of 
the lips, and the plants were kept outdoors under a fine net. The weather 
was moderate and clear, fairly dry, with day temperature 22° to 28°. The 
stigmas were not closed at first and did not close subsequently. They were 
watched for two days after pollination. Besides these series of experiments, 
many pollinations and closings of stigmas were made, generally resulting, 
unless a damp chamber was employed, in the pollinated stigmas remaining 
closed permanently. 
Generally, if the air is moist and the sky clouded, one will find the stigmas 
of Catalpa hignonioides open while the flowers are still on the tree. On 
the other hand, in sunshine, especially in the afternoon, the most of the 
stigmas are closed. The closing could be referred to the effect of the dry 
air, or to insect pollination, or to a combination of the two things. To 
determine whether the stigmas would close in usual weather, the open 
flowers were removed and discarded from several panicles on a part of the 
