day they are visited by bees and occasional butterflies, among 

 which the silver-spotted skipper {Epagyreus tityrus Fabr.) is 

 prominent. By four in the afternoon the corollas have closed 

 perceptibly, and by six they are almost completely folded. These 

 flowers will not open on the following morning, but bloom during 

 a single day only. Their period of full bloom is nine hours or less. 

 Out of fifteen flowers which had been marked, three shed the 

 furled corollas on the day after blooming, w^hile most of the 

 remainder fell during the following night, the second since their 

 anthesis. 



If the pollination of the flowers is prevented, the behavior of 

 the corollas is quite different from that sketched above. At 9 

 P. M. on August 12, eight large buds were enclosed in mosquito 

 netting bags, and of these, seven were in full bloom at noon on 

 the following day. They did not close that evening along with 

 the unprotected flowers, but remained open during the entire 

 night of August 13-14. At 10 A. M. on August 14 four of the 

 bags were removed and pollen was transferred on a small brush 

 to the stigmas of these flowers, while the remaining three were 

 left inside the bags to serve as controls. On the evening of the 

 same day the artificially pollinated flowers, which had been open 

 continuously for about thirty-two hours, closed along with the 

 undisturbed, insect-pollinated flowers which had come into 

 bloom that same morning. The unpollinated flowers were still 

 open on the following day. 



The normal behavior of the flowers of the shrubby althaea 

 {H. syriacus L.) of our hedgerows and flower gardens is practical- 

 ly the same as that of the swamp hibisci. Each blossom remains 

 open but a single day. After closing the corollas generally 

 remain attached to the receptable for a longer period than in the 

 case of the marsh-inhabiting species, and often dry up over the 

 pod instead of falling while still fresh. The corolla of H. Trionum 

 L., aptly called the flower-of-an-hour, has normally, according to 

 Kerner,* a period of bloom of about three hours, which makes it 

 the most ephemeral of all the species recorded in this author's 

 table of duration of anthesis. 



The dift'erence between the pollinated and the unpollinated 

 flowers of hibiscus raises a question in regard lo the above- 



* Kerner von Marilaun, Anton, Tlie Natural History of Plants, trans, by 

 V. W. Oliver. New York, 1895. See half-voliuue III, \). J 13. 



