Keirr — The Pollination of certain Species of Dendrobium. 53 



pollinia are caught by the stiff posterior border of the rostellum, which 

 scrapes them off the style and retains them in the stigmatic cavity. In this 

 species, then, self-pollination is prevented, as the pollinia are removed from 

 a flower before its stigma has opened out sufficiently to admit them. A 

 reference to PI. VI., figs. 4, 5, and 6, will better explain the structure of the 

 flower in this species. 



Dendrobium stuposum Lindl. — The filament is not very elastic ; but the 

 anther on dislocation falls over the entrance to the passage. Tliree out of 

 five self-pollinated flowers produced capsules. 



Dendrobiuni incurvum Lindl. (r*). — On dislocation the antlier falls forward ; 

 but the filament is not long enough to allow of the anther being pushed over 

 the stigma ; however, the dislocated anther would probably prevent access 

 to the stigma unless it was knocked off the filament. Five self-pollinated 

 flowers produced no capsules. 



Dendrobiuni beUatulum Eolfe. — The filament is slightly elastic ; but the 

 dislocated anther is with difficulty slioved on to the stigma. The passage 

 is very large, and only very partially blocked by the dislocated anther. 

 Two self-pollinated flowers produced capsules. 



Dendrobium ciliatum Parish. — The filament is very short. The anther, on 

 dislocation, does not block the passage ; any pressure from the front only 

 pushes it back into its original position. Although in this species there 

 is no mechanical contrivance to prevent a flower being pollinated with its 

 own pollen, my experiments show that self-pollination is not effective. 

 Sixteen flowers which were self-pollinated produced no capsules, two cross- 

 pollinated flowers producing good capsules. 



SOIENT. PROO. E.D.S., VOL. XII., NO. V. 



