30 



wind have little effect on nutation, but excessive 

 drought or moisture checks it almost entirely. The 

 stimulus which causes the stem to bend, is received 

 through the leaves, the terminal bud having nothing 

 whatever to do with it. When anthesis begins, nuta- 

 tion ceases and the disk turns over to the north-east. 

 This brings the flowers away from direct sunlight and 

 into the best position for the processes of pollination 

 and fertilization, and at the same time the bracts of 

 the head are brought with their outer surface into the 

 most advantageous position for the process of photo- 

 S3'ntax, and can thus continue the manufacture of food 

 which can no longer be transferred so readily through 

 the elongated and hardening stem. 



THE FERTILIZATION OF THE CLOSED GENTIAN. 

 R. J. Webb. 



The manner of fertihzation of the Closed Gentian, 

 ( Gentiana Andrewsii,) has been the subject of consider- 

 able difference of opinion, some, as Dr. Asa Gray, think- 

 ing it entomophilous while others have claimed it to be 

 entirely autogamous. 



It was my fortune one day last summer to observe 

 the fertilization of this Gentian in a way that would 

 seem to prove it insect-fertilized. 



On the morning of September 3, 1897, while walk- 

 ing by a moist piece of ground, I came across a fine 

 cluster of Closed Gentian ; my attention was also at- 

 tracted by three or four bumble bees which were buzz- 



